LOS ANGELES (AP) _ Convicted murderer Jeffrey MacDonald concocted a wild story to hide his guilt in the bludgeoning deaths of his pregnant wife and two young daughters, the former Green Beret's father-in-law testified.

''He told me so many (lies) ... it's very hard to recall them all,'' Alfred Kassab, testified Friday in federal court. ''It's a masterful con job that I got.''

He testofied in the breach-of-contract lawsuit filed by MacDonald against Joe McGinniss, author of the best-selling book ''Fatal Vision,'' that concluded MacDonald was guilty of the slayings.

MacDonald is seeking $15 million from McGinniss, accusing the author of deceiving him into believing he would write a book favorable to him.

MacDonald, 43, a physician and former Green Beret captain, is serving three consecutive life terms for the 1970 killings of Kassab's stepdaughter, Colette, and the couple's two daughters at their Fort Bragg, N.C., base home.

MacDonald, who told officers he and his family were attacked by drug-crazed hippies, claimed he suffered life-threatening injuries.

Kassab testified that MacDonald had only a bruise, small cuts and scratches after the brutal slayings.

Kassab, who spent less than 15 minutes on the witness stand, said he was upset by seeing MacDonald for the first time since the 1979 murder trial.

Kassab, of Jamesburg, N.J., said he changed the surnames on his stepdaughter and grandchildren's tombstones to Stevenson, Mrs. MacDonald's maiden name.