In the spring of 1978 House Speaker Thomas P. [Tip] O'Neil's lawyer son, Christopher, turned up in Saudi Arabia with a longtime family friend, David R. Thissen Jr.

With them was architect John Carl Warkecke.

The trio was there, Warnecke said last week, to line up business for themselves in Saudi Arabia's multi-billion dollar construction boom.

They found it. A joint venture involving Thissen and Warnecke in which they were awared a $1 million contract to draw up a master plan for the Royal Saudi Naval Academy and are now bidding to design the entire half-billion dollar project.

But Thissen, since the trip in 1978, has run into trouble in Massachusetts. He has become a target of investigation by the Special Commission on State and County Buildings, a blue-ribbon panel attempting to ferret out political corruption on Beacon Hill in Boston.

A close friend and golfing companion of Tip O'nEill's for 30 years, Thissen was reported by a source close to the investigation last week to have left the state. Attempts to serve him with a summons to testify have thus far been unsuccessful.

During the time Thissen owned the Boston firm of Desmond & Lord the firm did extensive work for public agencies in Massachusetts and the commission is looking into nearly every state contract received by the architectural design firm in the past decade and a half.

Warnecke bought Desmond & Lord from Thissen in 1979 after the commission's probe began. Thissen was kept on the payroll in an unspecified capacity, but still plays an active role, according to Warnecke.

Warnecke told a reporter last week that Christopher O'Neill had accompanied Thissen to Saudi Arabia "to introduce him to people." Warnecke said he did not travel with them but met them there.

Although Tip O'Neill's name has come up frequently as a longtime friend of Thissen's during the investigation in Massachussetts over the past 19 months, Christopher O'Neill's trip with Thissen to Saudi Arabia has never been mentioned before.

Warnecke said that he believed Christopher O'Neill was Thissen's "legal counsel" on the trip to Saudi Arabia. Warnecke said that he didn't know what expertise the 30-year-old O'Neill, an attorney just getting started in Washington, provided Thissen in a foreign country.

At the time of the trip, the name of O'Neill would have been one to open doors in Saudi Arabia. The trip came at a time when the Saudi Arabian government was pressuring the U.S. Congress to speed up sales of F15 jet fighters it badly wanted in a hurry.

On May 1, 1978, when a congressional floor fight was shaping up on the Saudi planes, Tip O'Neill gave supporters a boost when he announced that he would work for the speedy sale. It was approved two weeks later.

Warnecke said that O'Neill has done no work for him before or since 1978. "I've seen him socially in Washington, that's all," he said.

Neither O'Neill nor Thissen could be reached for comment last week. O'Neill's office said he had gone out of town on Friday morning. Warnecke's offices in New York and Boston said they could take messages for Thissen but declined to say where he could be reached. One secretary said she thought he "might" be in Florida.

Tip O'Neill was traveling and could not be reached for comment.