Washington area law enforcement officials announced yesterday that they had been conducting yet another massive undercover operation that attracted scores of criminal suspects who were conned into selling stolen property and drugs to undercover police officers.

In the fourth such operation in 18 months, undercover agents cruised the city in an ice cream truck and delivery vans and on motorcycles, purchasing waht law enforcement officials said was more than $1 million in stolen goods and $60,000 in legal drugs. As in previous operations, each transaction was taped by the undercover officers.

Aimed at locating and arresting fences who traffic in stolen goods and pushes who peddle narcotics, the latest operation, which was known as TRICONN, resulted in approximately 125 arrest warrants that were being served yesterday in the metropolitan Washington area. About 70 persons had been arrested by 6 p.m. yesterday.

Among those caught up in the undercover operation were two D.C. jail guards who were charged with robbing two of the undercover officers during a transaction; a suspect in a $30,000 jewelry robbery in Wilmington, N.C.; the alleged Washington manufacturer of high-profit bootleg musical tapes; persons who sold new cars they had stolen from showrooms; a postal worker who sold checks he had stolen from the mail, and a barber who was charged with selling large quantities of drugs in his Benning Road NE. barbershop.

Although law enforcement's top officials here publicly praised the operation as a resounding success at the now-standard press conference called at the end of the operation, numerous sources involved in TRICONN said the results were far less than expected for an operation that lasted 14 months and cost about $200,000 in federal grant money plus large amounts of police overhead costs.

The $1 million property values, for example, is based on the estimated original retail value of the goods purchased instead of their street value or their current resale value, these sources said. In addition, every stolen credit card was automatically valued at $500 in an attempt to inflate the total value of items recovered, they added.

Also, despite claims by top law enforcement officials that many of those charged with selling drugs were "mid-level drug pushers," other law enforcement sources made it clear that most of the 50 persons charged with drug offenses were actually street-level addicts who sold drugs to support their own habits.

These sources added that emphasis was shifted to drug cases and gun possession cases in the last few months of the operation in an attempt to boost TRICONN's arrest statistics after the operation was unsuccessful in penetrating high-level drug circles and major fencing operations.

However, none of this criticism of the operation was apparent yesterday when D.C. Police Chief Maurice Cullinane, U.S. Attorney Earl J. Silbert and FBI special agent-in-charge Nick F. Stames announced to assembled reporters at the fifth district police station yesterday that TRICONN had been concluded.

They said TRICONN was special because it showed a new undercover police mobility and unusual police ingenuity in going out to meet the criminals where they work - on the street - instead of forcing the criminals to come to a fixed warehouse or headquarters location, which had been the mark of three previous operations.

The first operation, with its flashy undercover police officers posing as out-of-town mafiosi, became known as Sting when it broke on Feb. 28, 1976. It ushered Washington into the area's myriad law enforcement agencies banding together under Law Enforcement Assistance Administration grants to lure unwitting criminals into locations where they committed crimes that were secretly videotaped.

The first Sting which resulted in nearly 160 prosecutions, operated out of a Northeast Washington warehouse not far from one of TRICONN's offices.

Next came G.Y.A. - the initials stood for "Got Ya Again" - which was unveiled on July 6, 1976, and resulted in 140 arrest warrants. It was run largely by black undercover officers who used an auto parts store in the Shaw area as a front for their fake fencing operation.

The third operation was unveiled on Feb. 26, 1977, and dubbed "Highroller" because the police operatives were headquartered in a plush suite in the Shoreham American Hotel. Although only about 15 persons were charged in connection with the expensive Highroller operation. its customers were self-described, high-level professional thieves who bragged of connections with organized crime.

Meanwhile, TRICONN had been ssecretly operating since the summer of 1976. It got its name because it was the third operation directed by a special unit of the Metropolitan Police Department, while Highroller had not ben directed by that same unit.

TRICONN also had its fixed bases of operation - a warehouse known as Delaney Enterprises at 1810 Edwin St. NW, where property was stored, and an office at 6527 Chillum Pl. NW - in addition to the roving 35 vehicles that were used to pick up merchandise from thieves who were too wary to come to a fixed location.

Cullinane said he believed the use of the vehicles "eliminated that last sanctuary" of thieves who thought they could avoid detection as long as they stayed out of warehouses that might be police operations.

"They might as well smile ehrn they're violating the law," Cullinane said adding that he believes criminals now have no way of avoiding police surveilance.

One of the most successful vehicles used, according to Cullinane and others, was the fully stocked ice-cream truck that the chief said sold ice cream to children at a profit while at the same time dealing with thieves.

As in previous operations, undercover officers working on TRICONN became involved in numerous unusual transactions during their 14 months of dealings with Washington's underworld.

Among the incidences recounted yesterday by police officials were:

The presentation of a letter to an undercover TRICONN officer from a group of friendly narcotics dealers, introducing the agent to a drug dealer in Thailand from whom he could purchase quality drugs. Also involved in the letter of introduction was a line of credit the undercover officer could establish with the dealer.

The issuance of arrest warrants for seven employees of the Central Delivery Service in Maryland, who reportedly were making drug deliveries to various locations in addition to their parcel deliveries.

Location of a stolen copying machine worth $22,000 that had been taken in a Virginia burglary.

Identification of a gang of juvenile and adult thieves who were directed by one man. Members of the gang were arrested when they were sent by TRICONN agents to burglarize the Edwin Place warehouse operated by TRICONN, only to be met there by a sign that said. "Welcome, Sting," and numerous police officers.

The arrest of a female post office employee who brought in hundreds of thousands of dollars in government checks she allegedly stole from the mail, including one stack of checks that totaled over $300,000.

The arrests of D.C. jail guards Ulysses Jones, 26, of 2853 Ontario Rd. NW, and Ronald A. Dock 27, of 1000 Rittenhouse St. NW. Both men were charged with robbery for their alleged part in attempting to hold up two of the undercover agents during a drug transaction.

The arrest of Reginald Robinson, 29, of 1920 Dutch Village Dr., Landover on charges of selling drugs at his "Mr. Natural" barbarshop at 3911 Benning Rd. NE. Officers who searched Robinson's house after his arrest said they found large quantities of drugs there.