Updated

As Thai police scour the island resort of Phuket, about 500 miles south of Bangkok, for a British kickboxer who allegedly killed a former U.S. Marine after provoking a barroom brawl, the American's Thai girlfriend is speaking out about witnessing his murder.

Police have named 28-year-old Lee Aldhouse of Britain as the prime suspect in the weekend stabbing death of Dashawn Longfellow, 23, who was vacationing on the island of Phuket and, according to U.S. media, a recipient of the Purple Heart after serving in Iraq and Afghanistan.

Thai authorities have issued an arrest warrant for Aldhouse and think he is still in the Phuket area but have alerted airports and sea ports in case he attempts to flee, said police Lt. Col. Anukul Nuket.

"It is very clear what happened," Anukul said. "Everything is very clear cut."

Longfellow's body was found before dawn Saturday at Phuket's Yanui Paradise Resort with several stab wounds in his chest.

Hours earlier the two men had come to blows at a local pub called the Freedom Bar, where the American was having drinks with a Thai girlfriend and Aldhouse picked a fight with him, police said according to witnesses. Witnesses described Aldhouse as a regular at the bar and known for "getting drunk and picking fights and bragging that he's invincible," Anukul told The Associated Press.

Both men were students of muay Thai, or Thai kickboxing, police said. Aldhouse had lived on-and-off in Thailand for four years and had competed on the club boxing circuit in Phuket, but police described him as currently unemployed. Videos posted on YouTube show Aldhouse in the boxing ring. One from 2006 refers to him as "Lee 'The Pitbull' Aldhouse." Another from 2009 shows him with several tattoos including one on his left shoulder that stretches down to the elbow.

But the American overpowered Aldhouse and apparently humiliated him, Anukul said. Onlookers broke up the fight, but the Briton allegedly followed the couple back to their hotel where Longfellow dropped off his girlfriend and went to a convenience store. Aldhouse reportedly followed Longfellow to the local 7-Eleven, where he acquired two knives, and then followed him back to his hotel.

"The American came back to see (Aldhouse) with a knife," Anukul said, citing witnesses. "He died from stabs to his chest."

A bloodied kitchen knife was found near the hotel, Anukul said.

Longfellow's girlfriend Oi said she saw Aldhouse approach her boyfriend from behind as he opened the hotel room door, Thailandnews.net reported.

"At first it didn't look like he had anything," Thailandnews.net quoted Longfellow's girlfriend. "We didn't know he had a knife because his hands were in his pockets." She said another fight broke out between the two and Aldhouse pulled out a knife and stabbed Longfellow twice in the chest.

Longfellow then reportedly was able to rush inside the room and shut the door as Oi called the police, but it was too late to save his life.

Longfellow had served in the U.S. Marines and was a machine gunner for the 2nd Battalion, 7th Marine Regiment, said Matt Gronbach, of Fort Dodge, Iowa, who was in the same unit with Longfellow.

"Dashawn was a caring and loving person. One of the nicest guys you could ever be around. Great friend, brother and son. He was just a huge teddy bear that everyone loved," Gronbach said in an e-mail.

Longfellow's mother, Tammy Longfellow of Norman, Oklahoma City, told Oklahoma City television station her son had traveled to Thailand to gain more knowledge about Thai kickboxing. Longfellow's passport was issued in Littleton, Colorado, according to Thai police.

Media reported that Longfellow was a Purple Heart recipient after serving in Iraq and Afghanistan. A Facebook memorial set up in his honor says he served two tours in the war zone and received "two Purple Hearts after being hurt by his vehicle exploding while he was there and going back to save who he could. He was awarded many more medals."

"He fought since the day he was born. He was three months premature and he made it through," his mother told the TV station. She said he joined the Marine Corps after graduating from high school in 2005 with hopes of traveling the world.

"He struggled in school, he made it through. He went to the Marines -- two wars he made it through. He goes over there to do something he loves and he gets killed," she said.

Click here to read more on this story from Thailandnews.net.