A Prince George's County grand jury, the Veterans Administration and the FBI are conducting a wide-ranging investigation of charges that some employes of an Arlington mortgage investment company forged and falsified information in loan applications submitted to federal agencies.

The investigation began early last summer, when VA officials noted what they said was an unusually high incidence of defaults on VA-insured mortgages in Prince George's County that had been handled by Hamilton Mortgage and Investment Co.

Sources said that since then investigators have uncovered evidence of a complex scheme in which debts were erased and savings and income were overstated on loan applications.

Accourding to sources, investigators also believe that, on some loans handled by some Hamilton employes, military veterans received kickbacks to allow other persons to obtain VA-insured loans in their names.

Gloria Ellison, a legal secretary who bought a home in Seat Pleasant through Hamilton, said yesterday that county investigators had called her in and asked her about a gift listed on her mortgage application "from a man I had never heard of." She said she was also asked to explain the deletion from her application of outstanding loans, which she said had been crossed off with a black felt-tipped pen. Ellison said she had filied out her application accurately.

According to sources, investigators have not determined whether the alleged abuses extend beyond a few employes of the company.

The president of Hamilton Mortgage, Lee A. Horner, said yesterday he was aware that a Prince George's grand jury was investigating charges against "employes of Hamilton," and confirmed that Hamilton had conducted an internal investigation of the charges.

Horner denied that the company had participated in any fraudulent loan practices.

One borrower, who said information on his loan application was falsified after he signed it, said that Hamiltons senior vice president S. Robert Pumphrey expressed concern that information had been altered and indicated that the company was prepared to move against any employes who might be involved.

Pumphrey's attorney, Louis J. Martucci, said yesterday that Hamilton had conducted its own internal investigation of the possible loan violations and had "come up with similar allegations." He said, however, that Plumphrey was not involved in the alleged abuses, had no knowledge of such while they were occurring, and was not directly involved in loan processing for the company.

Pumphrey, contacted Saturday, said he had no comment on the grand jury investigation or on a civil class action suit filed last week in Prince George's County Circuit Court. That suit, brought by Herald Pearsall, a Clinton man who defaulted on a loan from Hamilton charges Hamilton and Pumphrey with a series of activities similar to those already under investigation.

Pearsall alleged in his suit that Hamilton injured him and other mortgagees by "changed and increased mortgage payments, by placing people in homes they cannot possibly afford, and by use of false or forged documents in order to secure mortgage approval for individuals who lacked the sophistication of (the mortgage company)."

Sources said investigators are looking into whether fraudulent loan documents were used in a variety of profit-making schemes.

In some cases, employes of the company allegedly obtained loans for persons who did not qualify for them simply to increase the volume of business for the mortgage company, according to sources. Mortgage investment companies depend on service fees resulting from the sales of large numbers of loans to banks and insurance companies for the principal sources of income, according to a spokeman for the mortgage bankers' national association.

In other cases, borrowers have charged that their loan applications were changed after they submitted them, possibly so that the loan agreements would meet the requirements of dederal agencies that buy or insure loans made by mortgage companies.

An Veterans Administration officials, a source said, are investigating two cases in which they believe the names and qualifications of veterans may have been fraudulently used to obtain VA-insured loans. In one case, the source said, the veteran said he was not ever aware that his name had been involved.

In both cases, a source said, investigators believe that the house purchased with the assistance of the VA were rented out by a third party during the time before a foreclosure took place.

Two borrowers from Hamilton interviewed by The Washington Post yesterday said they learned of problems related to their loan applications only after they were contacted by investigators who questioned them about apparent discrepancies. Both borrowers said they submitted accurate information to the company.

Gloria Ellison, a legal secretary with two children who recently bought a house in Seat Pleasant, said she was called in for questioning by investigators in the state's attorney's office last summer.

When she arrived, she found that her loan application file included a form with her signature on it attesting to having received a gift of income from a man purporting to be her father "who I had never heard of." The file also showed her bank account to have more money in it than was true at the time of the loan application, she said. In addition, on a form where she had listed her debts, some were crossed out with a black, flet-tipped pen to give her a lower total of debts, she said.

Ellison said that the form with the false information about the gift from the strange man was a Xerox copy with her signature on it. Also, she said, "I did sign some blank forms, which was supposed to help me save time."

Another borrower, Dana Billingslea, said that he applied for his loan in October 1977 and was told that he was qualified. Subsequent to that, he said, he received a number of calls, including one from a federal auditor, questioning information he had submitted with his loan application.

"I called Hamilton and asked what was going on and asked about the loan," said Billingslea, an accountant with the federal Department of Housing and Urban Development.

Later, Billingslea said, he met with Pumphrey. "He told me that someone had altered my figures and the he was sure it wasn't me," Billingslea said. Billingslea said he qualified for the loan with some help from his parents and now lives in the house he financed through Hamilton.

The documents that he saw when he met with Pumphrey and later in a separate meeting with an investigator from the state's attorney office boosted his salary from $18,000 to $24,000 or $26,000, he said. They also minimized his outstanding debts, he said.

Billingslea said that his signature appeared on the altered documents but that the documents were photocopies.

County equity records show that Pearsall, the Clinton man who sued Hamilton in Circuit Court last week, obtained a $53,950 loan from Hamilton in December 1977, for a home in Clinton, even though he had defaulted on a loan from the Advance Mortgage Corp. of Delaware less than six months earlier.

In April of this year, according to court records, Hamilton filed a statement that showed that no payments has been made on the loan even though Pearsall had agreed to begin monthly payments of $444.01 in February.

In June, Hamilton bought Pearsall's home at a foreclosure sale for $56,697, according to court records. Hamilton officials later charged in court papers that Pearsall has refused to leave the house at 6809 Eilerson St., and a court granted a petition ordering him to leave. By Oct. 13, according to court records, Pearsall had moved out.

A VA official, who asked not to be identified, said that seven VA loans were under investigation by both the FBI and state's attorney's employes in Prince George's County.

He said that of the 4,000-5,000 loans insured by the VA in Prince George's County last year, only about 70 ended in foreclosure. Hamilton Mortgage, he said, was involved "in a suspiciously large number of foreclosures, considering how few we have."

In three of the VA cases, no payments were made on loans obtained from Hamilton and insured by the VA, the official said. In another case, three payments were made. The loans varied from a $36,500 loan made in March 1977 to a $53,500 loan made in April 1977, the official said.

In addition to the VA loans, county officials are looking into Hamilton 'loans backed by the Federal Housing Administration, as well as conventional loans.

When the FBI investigation is complete, evidence will be turned over to the U. S. attorney in Baltimore, the VA official said.

The Prince George's grand jury subpoenaed handwriting samples from Pumphrey and other Hamilton officials last month, in an effort to compare them with handwriting on loan documents, according to Martucci, Pumphrey's lawyer. But Martucci and five other attorneys representing other persons under investigation, managed to quash the subpoenas in a closed Circuit Court hearing, he said.

Hamilton Mortgage and Investment Co. was incorporated in 1970, according to corporate records in Virginia. In 1971, the company changed its name to Hamilton. According to records and sources, Thomas J. Broyhill and former U.S. respresentative Joel T. Broyhill helped set up the company.

According to the Mortgage Bankers Association's directory, Hamilton orginated 2,500 loans worth $93.3 million in the year ending June 30, 1977. In the same year the company listed its total assets as $22 million.