Pierce County prosecutors have charged an acquaintance of cop killer Maurice Clemmons with four counts of aggravated first-degree murder in the deaths of four Lakewood police officers last year.

Darcus Allen, who is suspected of driving Clemmons to and from the scene of the deadly shooting, will be arraigned on the charges – the state’s only crime that carries a possible death sentence – at 3 p.m. today in Courtroom 260. The charges were filed this morning, according to Superior Court records.

Allen, 38, has been in custody since Dec. 1.

Clemmons, 37, walked into a Parkland Forza coffee shop the morning of Nov. 29 and gunned down Lakewood police Sgt. Mark Renninger and officers Tina Griswold, Greg Richards and Ronald Owens. The four had been preparing for the start of their work day. All four died at the scene.

A Seattle police officer shot and killed Clemmons less than 48 hours later during a confrontation near an abandoned, stolen vehicle on a residential street. Clemmons was armed with the gun of one of the slain officers.

In the days after the officers were killed, law enforcement officers arrested seven of Clemmons’ family members and friends.

Six of them have been charged with various counts of rendering criminal assistance. Prosecutors allege they gave money, transportation and medical aid to Clemmons, who was shot by officer Richards, in the hours after the shooting at Forza.

Since his arrest in December, the 38-year-old Allen has been held on an Arkansas fugitive warrant as detectives investigated what he knew about Clemmons plans before the officers were killed and what he did afterward.

The Arkansas warrant charges Allen with robbery, theft and probation violations. Allen served time in an Arkansas prison after being convicted as an accomplice in a double murder 19 years ago.

Allen and Clemmons both served time in the Arkansas prison system. They spent as long as a month together in the 1990s in the same open barracks at two different units of the prison system, Arkansas corrections officials reported in December.

The open barracks are similar to military barracks. They house between 50 and 100 inmates, depending on the year and the prison.

UPDATE: According to charging documents just filed this morning, Allen knew Clemmons wanted to murder police officers and therefore was an accomplice to the crime.

Prosecutors contend that Clemmons made his plans known to Allen and others on Thanksgiving Day during a gathering at the home of Clemmons’ aunt.

At the time, Clemmons was wearing court-ordered ankle bracelet as a condition of his release from jail while awaiting trial on criminal charges. The bracelet alerted the bail bond company that posted his bail of his movements.

“He stated that he had or would cut off the ankle bracelet, luring police to his door, at which point he would shoot them,” prosecutors wrote in charging papers. “‘Knock, knock, knock, boom!’” he said, describing the planned murder.”

Clemmons also showed those gathered a gun he was carrying and said he had access to two others, the papers state.

The morning of the shooting, Clemmons allegedly drove a white pickup to Allen’s residence. Allen then drove the two of them past Forza, where they saw the marked patrol cars of Renninger, Griswold, Richards and Owens, the documents state.

Allen then turned around and drove back past the coffee shop and parked at a nearby car wash, according to the court records.

Clemmons then went Forza and opened fired on the Lakewood officers, being hit once himself when Richards fought him as he tried to flee.

Clemmons then returned to the car wash, where Allen drove him away, the documents state.

Witnesses told police it appeared that Allen was pretending to wash the pickup while Clemmons was in the coffee shop.

Allen and Clemmons sister, LaTanya Clemmons, later checked into a Federal Way motel under a false name and discussed buying Allen a ticket to Arkansas, according to court records.

Allen was arrested two days later and booked into jail on the outstanding warrants from Arkansas.

Allen first told police he and Clemmons only drove past Forza once, but video surveillance shows the truck coming back by the shop a second time, according to the court records.

Allen also told detectives he jumped out of the truck and ran when Clemmons returned from the coffee shop bleeding from a gunshot wound and that Clemmons drove the truck away, according to court records. Allen said he took the bus home.

“When the truck was recovered, however, there was blood noted on the passenger side, but none on the driver’s side,” prosecutors wrote in court records. “In addition, investigation revealed that no one matching Allen’s description took a bus from the location he described to his home, or anywhere near those locations.”

The charging papers conclude with this:

“Allen admitted to hearing Clemmons repeatedly talk about wanting to kill police officers. Allen also admitted to seeing the police cars outside the Forza, and he admitted to waiting at the car wash with Clemmons’ truck. While Allen waited there, Clemmons murdered the officers at the Forza.”