The name of an inmate who escaped from a Maryland prison by forging a release document was misspelled yesterday. The inmate's name is Floyd Haywood McIntosh Jr.

A 29-year-old inmate walked out of the Maryland state penitentiary at Jessup a free man last April on the strength of a release document that prison officials now believe was forged.

Corrections department officials issued an escape warrant this week for Floyd Haywood McIntoch, whose last known address was in the District. Officials also have begun an investigation into how McIntoch's prison release form, which did not have a key signature required for his release, had been forged and then processed.

The document bore the printed name of Prince George's Circuit Court Judge Audrey Melbourne, who had once refused to consider a request by McIntoch that his sentence be reduced. But it did not have the judge's signature, as is proper for prison release orders.

Also on the form was what appeared to be a Prince George's County seal, and the signature of Norman L. Pritchett, clerk of the county Circuit Court. Court officials said Pritchett did not sign the release order.

McIntoch was serving a seven-year sentence for breaking into a local drug store in 1978.

Prison officials yesterday refused to comment on the case, adding to growing confusion over how the original release document, which normally must be delivered from the county courthouse, reached prison officials and led to McIntoch's release. Even yesterday, court officials, who have Xerox copies of the forgery, were unsure of the whereabouts of the original form.

Court officials said yesterday that McIntoch and his cellmate worked in the prison library and may have had access to information that could have enabled someone to forge a release form.

Suspicions about McIntoch's release first arose last week, when Jessup officials phoned the court clerk's office, where copies of the release forms are on file. Prison officials asked a clerk to check McIntoch's criminal records to verify the existence of a document labeled "Order for Reduction of Sentence." The clerk's office discovered that the document did not exist, and asked to have a prison copy sent to the court for inspection.

"They sent us a copy last Friday and we realized that it was not one of our pleadings," said Shirley Hill, chief deputy to the clerk, adding that a proper court order would have been signed by a judge, not Pritchett. Hill said that the photocopy sent to her office also bore a faint circle that appeared to be an official county seal.

When suspicions continued to mount, prison officials called the judge to ask if she had issued an order to release McIntoch. Melbourne said she had never granted a release order and told officials that in August 1980 she had denied his motion to have his sentence reconsidered.

It was unclear yesterday what led officials at Jessup to begin to suspect that McIntoch should not have been released.

According to court records, McIntoch, who listed his address as 1603 Evarts St. NE, was convicted of breaking into a Peoples Drug Store in Prince George's County on June 5, 1978. Six months later Melbourne gave him a 10-year suspended sentence with five years probation on condition he attend Second Genesis, a drug-rehabilitation center.

McIntoch stayed at the program only three days before running away, according to court records, and a bench warrant was issued for his arrest. In July, 1980, citing the violation of his probation, Melbourne ordered him to serve seven years of his original sentence.