Sydney - A relative was arrested Tuesday over the gangland killing of the last male member of Australia's infamous Moran crime family.

Sister-in-law Judy Moran was taken into custody a day after the execution-style killing of Des Moran in a Melbourne cafe, and is expected to be charged with being an accessory after the fact.

Three others have been arrested, at least one of whom is expected to be charged with murder.

Assistant Police Commissioner Dannye Moloney said a family feud rather than a turf war might explain why Des Moran was gunned down by two masked assassins.

"I'm satisfied that this murder is not connected ... to the gangland murders," Moloney said.

Judy Moran lost her first two husbands and her two sons in the 8-year, tit-for-tat slayings. Most of those who engaged in the killings - at least 28 have died - are either in jail or themselves dead, police said.

A witness to Monday's lunchtime murder said he saw a tearful Judy Moran on the scene minutes after the shooting.

Two months ago, Des Moran survived an attempt on his life by a single gunman he derided as an amateur. "If he'd been fair dinkum, he'd have fired five or six shots, wouldn't he?" Des Moran said at the time.

Carl Williams, who is serving 35 years for his part in the elimination of the Morans, said through ex-wife Roberta Williams that he was surprised by the latest Moran death.

Roberta Williams herself expressed both surprise and disgust in an interview with The Australian newspaper.

"If they are willing to kill some defenceless drunk like Des, who else are they prepared to kill?" she asked? "I mean, where the fuck does it all end? You can't even have a fucking cup of coffee without getting shot these days." (dpa)