LOS ANGELES -- Anthony Wayne Smith spent seven years as a menacing defensive end for the Oakland and Los Angeles Raiders whose mission was to put quarterbacks on the turf.

Authorities believe that penchant for a game of violence turned into something more sinister shortly after Smith departed professional football.

Already awaiting retrial for a murder four years ago, Smith was charged this week with three additional murders, including the slayings of two brothers who prosecutors said were kidnapped and robbed by men posing as police officers.

The most recent charges paint a portrait of a man who authorities say turned to brazen crime, but leaves the question of why he needed to after a somewhat successful career.

Smith, now 45, was drafted 11th overall by the Raiders in 1990 and amassed 57½ sacks and 190 tackles while as a defensive end in the NFL. In 1993, Smith had 12½ sacks, helping put the Raiders in the playoffs. The team lost in the AFC divisional round to Buffalo 29-23.

Smith retired in 1998 and according to authorities took part in the murders of Kevin and Ricky Nettles in November 1999.

The siblings were kidnapped from a car wash in Los Angeles by two men posing as police officers, and they were later found shot to death, said Sandi Gibbons, a spokeswoman for the Los Angeles County district attorney's office. The victims' bodies were dumped about eight miles apart from one another.

Smith also was charged in the June 2001 killing of Dennis Henderson, who, along with another man, was kidnapped in Los Angeles by several gunmen, Gibbons said. The victims were put in separate cars, and while the other man was let go, Henderson's body was found in a rental car. Authorities said Henderson was beaten and stabbed to death.

Los Angeles police detectives began working on the trio of old murders in April 2011. Several search warrants were served and witnesses were interviewed, said police Cmdr. Andrew Smith. Investigators wouldn't say if Smith knew the Nettles brothers but said the former NFL player lived next door to Henderson's brother.

"We believe these were robberies, but we don't know the motive behind them," said Smith, who has no relation to the suspect.

Defense attorney Michael Evans declined comment about the new charges, saying he hasn't seen the evidence against his client.

In a court filing, prosecutors said all three victims were tortured. Smith also faces three counts of kidnapping, and along with special circumstances, is eligible for the death penalty. Prosecutors will make a decision on whether to seek capital punishment at a later date.

Meanwhile, Smith is jailed awaiting retrial on a murder charge in the 2008 killing of Maurilio Ponce. A jury failed to reach a verdict in April, splitting 8-4 in favor of guilt.

Prosecutors contend Smith lured Ponce to an Antelope Valley desert highway where the mechanic was beaten, stomped and shot over a business deal gone wrong.

Evans argued at trial that there was no physical evidence linking his client to the crime and Smith had no reason to kill Ponce.

Smith will be retried with a co-defendant. A third man, Eric Honest, was convicted of second-degree murder in April and is awaiting sentencing.

Smith's next court date is July 17.