ST. LOUIS • A lawyer for the young child of a man killed by St. Louis police in December said today he will file a lawsuit alleging that officers shot him even though he was unarmed and pleading for his life.

Albert Watkins, the attorney, said he expects to file suit Monday in U.S. District Court.

A police spokeswoman confirmed today that the department has asked the FBI to look into the case at issue, the Dec. 20 death of 24-year-old Anthony Lamar Smith. The FBI confirmed that it was being done.

Christina Wilson, 31, Smith's pregnant girlfriend and mother of their 1-year-old daughter, told the Post-Dispatch at the time that she was on a cell phone call with him when he was shot.

"He was crying for help, " she said softly. "I could hear him moaning, ‘Oh, oh.'"

Watkins alleged that an officer, whose name he did not reveal, planted a firearm on the dead man afterward.

The lawyer also claims the officer brandished what appeared to be an AK47 rifle at one point but did not fire it. Police policy requires officers to use only department weapons, which do not include that type.

Watkins said the claims are based in part on what Wilson heard during the call.