A Mexican judge, his secretary and two jail employees were under investigation Monday after a man accused of killing a vacationing Colorado university student escaped from jail.

Local prosecutor Guillermo Martin Diaz said the four may have played a role in helping Alfonso Ramirez walk out of a Puerto Vallarta jail early Friday.

Ramirez is accused of killing 21-year-old David Parrish of Boulder, Colorado, during a robbery on Wednesday.

Diaz told a news conference Monday that officials want to know why the judge and his secretary issued a release order and the two jail employees let Ramirez go, all before dawn Friday.

The two jail employees have been detained since Friday. Officials are looking for the judge and his secretary.

The city's public safety director also has been suspended without pay pending an investigation of the escape.

Local police initially said Ramirez tricked guards into releasing him by switching clothes with a cellmate who was being held for robbing a bottle of liquor.

U.S. Embassy spokeswoman Judith Bryan said the killing was the first fatal shooting of an American in Puerto Vallarta that the Embassy had on record. About 1 million Americans visit Puerto Vallarta each year.

She said U.S. officials were working with their Mexican counterparts to ensure that the suspect was detained again and anyone responsible for aiding the escape faced justice.