[This story was updated on 05.19.2003 at 9:12 p.m. ET.]

Stone Temple Pilots singer Scott Weiland was arrested for investigation of drug possession on Sunday in Los Angeles.

The troubled singer, who recently cut two songs with former members of Guns N' Roses and has been heavily tipped as the lead singer of what's currently dubbed "The Project," was released on $10,000 bail after police stopped him early Sunday morning for a minor traffic violation and found what they believed to be drugs, according to Burbank Police Lt. John Dilibert.

"He was parked in a darkly lit area and he drove off with his lights off, after which the officers stopped him," Dilibert said. Police searched the car and found what they believed to be an illicit substance, which Dilibert said they have not named, pending further tests. Under the felony code for which Weiland was arrested, Dilibert said the charges could relate to everything from cocaine and heroin to Vicodin. A 29-year-old woman traveling with Weiland was also arrested on the same illegal substance possession charges.

Weiland's manager, Peter Katsis, recently confirmed that the 35-year-old singer had been enrolled in several drug rehab programs. Katsis had no comment on the arrest, however. Weiland's lawyer did not respond to calls, and a label spokesperson had no comment.

Weiland posted bail around 5:30 a.m. Sunday and is scheduled to be arraigned on June 2. Dilibert described the area in which Weiland was arrested as a "business district that was closed up that time of night."

The STP frontman has struggled with drugs for nearly a decade and has been arrested three times in the past for possession — twice in California, which makes him a third-time offender in that state. Weiland was arrested in 1995 for possession of heroin and cocaine and was spared jail time on the condition that he undergo drug counseling. He received court-ordered hospitalization related to those charges in 1996 (see "Weiland Back In Rehab").

Weiland voluntarily checked into another rehab facility in 1997 (see "Weiland Back 'Under Care' "), only to be arrested later that year in Los Angeles on felony heroin possession charges during a traffic stop. In June 1998 he was arrested for heroin possession yet again, this time in New York (see "Scott Weiland Arrested In Heroin Bust").

After being treated for a heroin overdose in July 1999, Weiland was arrested for violating his three-year probation for the 1997 arrest and was sentenced to spend one year in a jail recovery center (see "Stone Temple Pilots' Weiland Ordered To A Year of Rehab"). He was released the following January but remained in a supervised treatment program.

He was arrested in November 2001 and pleaded guilty to a battery/domestic violence charge stemming from an altercation with his ex-wife, Mary, who told police the incident began when she tried to prevent him from refilling a prescription medication (see "STP's Weiland Ordered To Attend Counseling After Guilty Plea").

In between working on his second solo album, helping out Michelle Branch on her upcoming disc (see "Michelle Branch Going Organic, With Help From Scott Weiland, For Next LP") and co-producing Cinder's debut, Weiland has been jamming with ex-Guns members Slash, Duff McKagan and Matt Sorum for their still-unnamed band (see "Slash/ Duff/ Matt Coming Soon, Axl Nowhere In Sight"). Weiland will be heard in the upcoming film "The Italian Job," for which the group recorded a cover of Pink Floyd's "Money" with Ziggy Marley and keyboardist Teddy Andreadis, who toured and played with Guns during their Use Your Illusion period.

The band also recorded an original song, the blistering "Set Me Free," for the big-screen adaptation of "The Hulk." Neither song will be on a soundtrack, though both are expected to be used in the closing credits.

While Weiland was recently quoted as saying that he is the official singer for the Project, Slash's publicist said the final paperwork on the deal has not been signed. "This [arrest] doesn't affect the decision to have Scott be the singer, because there is no decision," the guitarist's spokesperson said. "Nothing has stopped. We're just trying to see where this leads."

Sources close to the group said Weiland's ongoing drug issues are a source of frustration for the rest of the band. "The dude is an addict trying to be in a band with former addicts," one source said. "You do the math."

Should Weiland be selected as the singer for the Project, plans are being made to help lessen the risk of a relapse, including possibly 24-hour supervision and a full round of rehab before any larger commitment takes place. "He has issues he has to deal with, and everyone is trying to make this happen knowing that," one source said.

A source close to the singer said this arrest may help save Weiland's life: "It could be a blessing, who knows? Jail is the only thing that has succeeded in getting him clean for any length of time."

Weiland faces up to one year in county jail if convicted.