West Valley City • More than 11 years after a West Valley City man was found dead on the floor of his pool hall, police say they think they finally know who killed him.

West Valley City police arrested 37-year-old Tien Truong Nguyen on Thursday. He was booked into the Salt Lake County jail on suspicion of homicide and obstruction of justice in the killing of 36-year-old Tri Xuan Phan.

(Courtesy West Valley Police) Tri Xuan Phan

On Jan. 10, 2007, police went to Vui Vui Billiards in West Valley City and found Phan dead. An autopsy later revealed he died from blunt force trauma and stab wounds, Deputy Chief Matt Elson said at a news conference Thursday.

Police said multiple weapons were used in the killing.

They interviewed “dozens and dozens” of witnesses and investigated the crime scene but weren’t able to make an arrest, Detective David Greco said. No evidence found at the scene was connected to anyone interviewed, he said.

But they recovered a key piece of evidence: a fingerprint left in Phan’s blood. Police believed it belonged to the killer, but when they ran it through a database they came up empty.

But in 2015, Nguyen was arrested by Unified police for aggravated assault, and his fingerprints were added to the state database, Greco said. Greco, who investigates all of the department’s cold cases, said fingerprints in cold cases are routinely run through the state database, but it took a while for the database to update following the 2015 arrest.

(Photo courtesy of the Salt Lake County jail) Tien Truong Nguyen

In April 2016, West Valley City police got a hit on the bloody print. They renewed the investigation, Greco said, and on Thursday Nguyen voluntarily came into the station and was interviewed by police.

“He did indicate that there was an altercation,” Greco said. “And that he did at one point go back to our scene and attempt to clean the scene and hide evidence.”

Phan was at the pool hall cleaning up after the business closed for the night, police said. There was no sign of forced entry, so police believe Nguyen was either invited in or the door was unlocked.

Greco said he doesn’t know if the two men knew each other, and that police don’t believe anything was stolen from the pool hall.

Greco declined to discuss the case further, saying it is still being investigated.

Although Phan’s death was apparently preceded by a “violent struggle,” the case eventually went cold. The police department had asked the public for help in solving the case around the eight-year anniversary of Phan’s death.

Greco said when he opens up a cold case, he starts the investigation all over, including conducting new interviews with witnesses and looking over the entire investigation. Greco said that, along with requesting documents, is why it took nearly two years to make the arrest.

Greco said Nguyen was not a suspect back in 2007 and that he has remained a West Valley City resident.

Greco said this arrest is an example that while some cases run cold, the department continues to investigate and doesn’t give up hope.

“When we got the lead, it was refreshing to be able to put a name to some evidence,” Greco said.