A man already charged with two homicides in Seattle and a third in New Jersey was charged Wednesday with an additional count of aggravated first-degree murder in the April drive-by slaying of a Skyway man.

That makes a total of four murder charges filed against Ali Muhammad Brown, 29, a self-proclaimed Muslim jihadist who allegedly claimed he killed the men to do his “small part” in avenging the deaths of Middle Eastern citizens at the hands of U.S. forces, charging documents say.

In the most recent charges, Brown is alleged to have fatally shot Leroy Henderson, 30, of Skyway, on April 27.

According to the charging document filed in King County Superior Court, detectives investigating the Skyway shooting found 9mm bullets and casings that were stamped “F C 9mm Luger.”

They also were able to locate a nearby residence that had surveillance cameras and to discern some distinguishing characteristics of the suspect’s vehicle, which appeared to be a 2006 to 2009 Dodge Durango with a missing front license plate and a broken back center brake light, court documents say.

Sheriff’s investigators called Seattle police on June 9 to share information and ask if a vehicle matching the description of the Skyway shooter’s SUV was believed to be involved in any Seattle crimes, the court documents say.

The following day, a Seattle homicide detective called sheriff’s investigators to say they were working on a double homicide in Seattle’s Leschi neighborhood that occurred on June 1.

Seattle police said they found spent 9mm cartridge casings head-stamped “F C 9mm Luger” at the Leschi site where Dwone Anderson-Young, 23, and Ahmed Said, 27, were found slain.

Police said in charging documents that Brown was in one of the Seattle victim’s cars after the three had been at a Capitol Hill nightclub when Brown pulled out a gun and killed the men.

Prosecutors say Seattle police were able to get a palm print from inside the victim’s car that was matched to Brown.

Investigators also determined that a Dodge Durango matching the one seen at the Skyway slaying was registered to Brown’s girlfriend, court documents say.

After the Leschi slayings, Brown was identified as a suspect. However, police believe he fled to New Jersey.

Brown was arrested in New Jersey last month after police and prosecutors say he shot and killed Brendan Tevlin, a 19-year-old college student, in West Orange on June 25.

Acting Essex County Prosecutor Carolyn Murray said last month that Brown, Jeremy Villagran, 19, and Eric Williams, 18, had pulled up next to Tevlin at a stoplight. Brown and Villagran got out and one of them briefly spoke with Tevlin before Brown, who was standing at the passenger side, fired 10 shots — eight of which struck Tevlin, according to the website nj.com.

Brown has been charged in New Jersey with murder, felony murder, robbery, conspiracy and weapons offenses. He is being held in lieu of $5 million bail.

Testing done by the Newark Police Department Crime Lab determined that a 9mm handgun found on Brown was used to kill all four victims, according to the report.

Brown — who has a previous criminal history that includes convictions for conspiracy to commit bank fraud and communication with a minor for immoral purposes — has pleaded not guilty to the New Jersey homicide.

It is unclear when he will return to Washington on the three King County murder charges.

County prosecutors said they have not decided if they will seek the death penalty against Brown.

“We are in communication with the prosecutors in Essex County (N.J.) regarding their murder and robbery charges,” King County Prosecutor Dan Satterberg said in a statement. “I expect that eventually Brown will come back to King County to face the three aggravated murder charges we have filed, but precisely when that will be remains unclear at this point.”

According to charging documents, Brown claims to be Muslim and a jihadi.

He told investigators that the shooting of the four victims in the Seattle area and New Jersey were “just kills,” or justified shootings of adult males in retaliation for actions by the U.S. government in Iraq, Syria and Afghanistan.

“All these lives are taken every single day by America, by this government. So a life for a life,” Brown allegedly told investigators.

Seattle police said Brown is also wanted on warrants for failure to register as a sex offender. In March 2012, Brown pleaded guilty to communication with a minor for immoral purposes and was sentenced to a year in jail.

Brown served federal prison time for conspiracy to commit bank fraud in connection with a plot to defraud several banks.

In that case, between January 2002 and November 2004, Brown and three other men defrauded U.S. Bank, Bank of America, Key Bank, Washington Mutual, Wells Fargo and Boeing Employees Credit Union by depositing counterfeit and fake checks, then withdrawing funds before the checks were returned, according to charging documents filed in U.S. District Court.

Authorities determined that the men involved were supporting terrorism in Somalia.

Christine Clarridge can be reached at cclarridge@seattletimes.com or 206-464-8983. Seattle Times researcher Miyoko Wolf contributed to this story, which includes information from Times archives.