PUERTO VALLARTA, Mexico -- Two Mexican judges said they accidentally released a suspect in the shooting death of a vacationing University of Colorado student.

Municipal judges Jesus Roberto Gomez and Jorge Alejandro Garcia appeared before the Public Ministry Tuesday. Officials are trying to find out how a man accused of killing 21-year-old David Parrish, of Boulder, escaped from jail.

City officials said they wanted to know why Gomez issued a release order and two jail employees let the suspect go on Friday before dawn -- an hour at which releases are unusual.

The jail employees were being held Tuesday at a state prison.

Police initially said suspect Alfonso Ramirez tricked guards into releasing him by switching clothes with a cellmate, who was being held for allegedly stealing a bottle of liquor.

The judges, who have legal protection from being arrested, said they intended to release the liquor suspect because prosecutors had not pressed charges against him.

Sastre was arrested with another man, Daniel Vargas Castaneda, by Mexican police on suspicion that they shot and killed David Parrish.

Parrish was shot on March 26 near the cruise ship port.

Parrish's mother, Janet Graaf, was reportedly with him at the time of the shooting and said that her son tried to stop the men from taking her purse. She had just visited an ATM. Graaf is an instructor at CU's Leeds School of Business.

Parrish graduated from Boulder High School in 2005 and was studying geography at CU, according to school records. He grew up in Boulder.

A memorial service to honor Parish will be held at 2 p.m. Friday at St. John's Episcopal Church, 1419 Pine St., Boulder.

U.S. Embassy spokeswoman Judith Bryan say the killing was the first fatal shooting of an American in Puerto Vallarta the Embassy has on record. About one million Americans visit Puerto Vallarta each year.