"Why? Why? Why?" the mother of Ahmed Diallo cried during a visit to the scene of the shooting, after she arrived in New York from Guinea in West Africa.

"Amadou! Amadou! Amadou!" Kadiadou Diallo wailed, using her endearing name for her son, as she entered the lobby of the building in Soundview where four plainclothes cops fired 41 shots at her 22-year-old son last Thursday, hitting him 19 times.

As 3,000 protesters were gathering at Foley Square near City Hall to express their outrage, the victim's mother had to be helped by friends into the small apartment her shy son shared with others after immigrating here legally three years ago.

"I want to die instead of him," she said, stepping into the room where he slept.

Up and down the Bronx street, as well as around City Hall and Foley Square yesterday, many people were moved to tears and anger by the murder of Amadou Diallo.

"When I see things of this nature, my heart grieves and I too wonder why," said Audley Fogo, a transit worker who wept softly as he watched the victim's mother.

Diallo was killed shortly after midnight six days ago, as he was entering his apartment, by — members of the NYPD'S undercover street crime unit (whose motto is "WE OWN THE NIGHT) —

The Bronx district attorney may impanel a grand jury later this week, and the FBI and the Manhattan U.S. attorney are monitoring the investigation.