Master burglar Bernard C. Welch, the man convicted of the 1980 murder of physician Michael Halberstam, gave his female companion more than $1.1 million in 1978 and 1979, telling her it came from his "investments" in stocks, real estate and coins, according to court testimony.

In a hearing in federal district court here yesterday, Linda Sue Hamilton, Welch's companion for five years, acknowledged receiving the money and filing income tax returns for it, but said she believed it came from legitimate businesses. She also said later that all the money has been spent or attached by creditors and the Internal Revenue Service.

Her testimony came in a hearing on an $81 million lawsuit filed by Halberstam's widow, Elliott Jones, against Welch and Hamilton. In the lawsuit, Jones claims that Hamilton and Welch, whom Jones described as Hamilton's "partner and agent," were in a "joint criminal venture and conspiracy," in the course of which Welch shot and killed Halberstam during a burglary of their Northwest Washington house.

Welch was convicted last April of murdering Halberstam and sentenced to 143 years in federal prison. No charges have been brought against Hamilton in connection with any of Welch's activities.

Hamilton's attorney, Albert J. Ahern, told Judge Aubrey E. Robinson Jr. that Welch had "fooled and used a lot of people," including Hamilton, who he argued was a "used victim." Ahern said there is "no basis, not a scintilla of evidence to connect her" to Welch's crimes.

"However much we sympathize with Halberstam and his family," Ahern said, we can't hold her Hamilton responsible for Welch's sins."

Jones has acknowledged that it is unlikely that she would recover damages from Welch. She said yesterday in an interview that she filed the suit as a "protest and for revenge," stating that she feels "hatred" for Hamilton and any others who might have profited from Welch's career as a burglar. Police believe Welch may have been responsible for more than 200 Washington area burglaries.

"She Hamilton knew what was happening whether she wanted to acknowledge it or not," Jones said. Jones' lawyer, Jacob A. Stein, told Robinson it was "incredible" that Hamilton never questioned Welch about the source of such "startling" amounts of money.

Robinson, who said the issue was "too close" for him to rule without further arguments, asked both sides to submit memoranda on their cases within the next two months. He will rule eventually on whether Hamilton is liable for damages and, if so, how much money should be awarded to Jones.

Hamilton said in an interview that she is unemployed and supporting Welch's and her three young children with money from her parents. She said she recently applied for public assistance in Great Falls, where she rents a home, but was rejected.

Hamilton said her sprawling $1 million ranch home in Great Falls, which she put on the market last summer, is still for sale, as is another home the couple had in Duluth, Minn.

Hamilton's accountant, Sidney W. Macauley Jr., said that much of her money was lost in speculative investments Welch made, and that the IRS, which has filed $24 million in tax liens against both Welch and Hamilton, "took what was left," which he said was "not much."

Welch, who was sentenced to 30 years in prison last week in Montgomery County for four burglaries and one armed robbery, was returned Monday to a federal prison in Marion, Ill.