San Diego hotel clerk goes on a stabbing spree, attacking young female guest before fleeing and driving his car off a pier

A hotel desk worker threatened a young female guest in her room before stabbing her and driving his car off a pier.

Aaron Tran, 23, was found drowned in his white Honda Accord near the USS Midway Museum in downtown San Diego early on Monday morning.

He was submerged under 40ft of water after doing doughnuts in the streets and  deliberately zipping off the jetty at 80mph.

The perplexing events began when Tran checked in two women in their 20s from outside the state to a room at The Shoal La Jolla Beach.

The perplexing events began when Aaron Tran checked in two women in their 20s from outside the state to a room at The Shoal La Jolla Beach

The perplexing events began when Aaron Tran checked in two women in their 20s from outside the state to a room at The Shoal La Jolla Beach

A few hours later, he called the room to say he needed to get inside to fix a water leak, which police said didn't exist.

One of the women let him inside while her friend was asleep on the bed, and they walked towards the bathroom before he handed her his phone.

'She looked at his phone and on his phone he had written something to the effect of, "Don't scream, I have a knife. If you scream, I'll stab you". When she looked up, he was holding a knife,' San Diego Police Lieutenant Paul Phillips said.

Instead, the woman fought back and was stabbed, suffering a glancing wound near her collarbone.

She screamed loud enough to wake up her friend and they escaped together while Tran fled the building to his car about midnight.

He was seen speeding around downtown and doing doughnuts by various witnesses, and a patrol cop tried to pull him over.

Tran revved his engines and drove off the pier at speed, splashing into the bay and sank to the bottom within 10 minutes.

Tran's body is seen floating in the water after Harbor Police and teams of San Diego Lifeguards pulled him out from his submerged vehicle

Tran's body is seen floating in the water after Harbor Police and teams of San Diego Lifeguards pulled him out from his submerged vehicle

Officers pull Tran from the water. They discover he has self-inflicted stab wounds to his chest and collarbone area

Officers pull Tran from the water. They discover he has self-inflicted stab wounds to his chest and collarbone area 

Pictured: Tran's white Honda Accord being pulled out of the water by authorities on the scene

Pictured: Tran's white Honda Accord being pulled out of the water by authorities on the scene

San Diego Police stand around Tran's water logged and incredibly damaged car. This comes after divers pulled Tran's body out from the car

San Diego Police stand around Tran's water logged and incredibly damaged car. This comes after divers pulled Tran's body out from the car

San Diego Harbor Police said he went off the pier about 12.35am and his body was recovered by divers about 2.20am.

Phillips said Tran had several stab wounds near his collarbone but he wasn't injured in the struggle in the hotel room.

At least one of the wounds was self-inflicted and a pocket knife was found in the car, which was eventually winched out of the water about 5.30am.

Tran's shift ended at 10pm and police were combing through security footage to figure out what he did in the almost two hours before the attack.

He worked at The Shoal for about six months, had no criminal history, and lived with his parents.

His motive for the hotel room attack was under investigation. Police are checking his fingerprints and DNA against other unsolved crimes.