A 16-year-old girl was arrested Wednesday in the fatal shooting of a 47-year-old man at a SeaTac motel earlier this month, according to the King County Sheriff's Office.

Sheriff's spokeswoman Sgt. Cindi West said Thursday that more arrests are expected. Detectives are also asking for the public's help in locating 19-year-old Kavahn Matthews-Smith, who lives in the Skyway area and is considered a suspect in the Sept. 7 slaying, she said.

Matthews-Smith is described as African American, 6-foot-5, 180 pounds, with black hair and brown eyes. Anyone with information is asked to call 911 and reference case number 12-210242.

The victim has been identified as Herman Herlondo Tucker, according to the King County Medical Examiner's Office, which determined that Tucker died from multiple gunshot wounds. Tucker lived in Skyway.

West said that robbery is a likely motive for the shooting, but detectives are still investigating what Tucker was doing at the Motel 6 in the 20600 block of Military Road when he was killed.

The 16-year-old girl was arrested at the intersection of 23rd Avenue and East Cherry Street in Seattle early Wednesday, according to the statement of probable cause outlining the police case against her. A judge Thursday found probable cause to hold her in custody on investigation of first-degree murder, said Dan Donohoe, spokesman for King County Prosecutor Dan Satterberg.

Prosecutors are still reviewing the case, but it is expected that the girl will be charged as an adult, he said.

State law requires that 16- and 17-year-olds accused of serious, violent crime automatically be charged in adult court.

According to the probable-cause statement, Tucker "picked up" the 16-year-old the evening before he was shot, and the pair went to the Motel 6. Detectives determined that Tucker was checked into room 224, and they got a warrant to search the room, locating two cellphones inside, one of which belonged to Tucker, the statement says.

On the other phone, detectives found text messages detailing a plan "to rob Tucker of his rings and possibly cash," the probable-cause document says. "Investigators noted that Tucker died with multiple rings on his fingers and about $700 in cash in his wallet," the statement said.

According to the statement, witnesses saw the girl fleeing the scene with three males in a BMW driven by a woman.

The Sheriff's Office, which provides police services to the City of SeaTac, previously said witnesses reported that Tucker arrived at the motel in a white SUV around 3 a.m. and first tried to get inside a room using a key card. When the door did not open, he knocked and was let inside.

Within a few minutes, an argument could be heard coming from inside the room and then witnesses heard gunfire, the Sheriff's Office said at the time.

Tucker stumbled out of the room and collapsed.

The Sheriff's Office initially reported that two men and two women were then seen fleeing the room, partially covering their faces with T-shirts. They drove off in a dark-colored vehicle, possibly a BMW, according to the Sheriff's Office.

Tucker was the father of two Federal Way High School student athletes.

According to a post on Facebook, Tucker was also a coach in the South King County Junior Football League.

Sara Jean Green: 206-515-5654 or sgreen@seattletimes.com

Seattle Times news researcher Miyoko Wolf contributed to this report.