By Laila Kearney

(Reuters) - The youngest son of U.S. Representative John Conyers was found safe on Friday after his disappearance in Texas earlier this week triggered a search that included police, the FBI and Secret Service.

Carl Conyers, 21, a student at the University of Houston, was located by university authorities at his Houston apartment complex at about 1 a.m. CST, a city police spokesman said.

Conyers, who had last been seen on Tuesday, was interviewed by detectives and released to family, the spokesman said.

Investigators still are seeking to determine where Conyers had been and why he abruptly cut off contact with family and friends.

Conyers' mother, Monica Conyers, told KHOU-TV that her son was in need of a shower and had not eaten when he was located but was in otherwise good condition.

Houston police did not immediately return a request for comment.

His mother said Conyers told roommates he "had a bad day" the day he went missing, KHOU reported.

He was last seen on Tuesday afternoon by his roommate at their Houston apartment, police said. On Wednesday, messages were sent from Conyers' social media account to his girlfriend, Daisha Lewis, and several friends asking them to meet him at the university, Lewis told WWJ Newsradio in Detroit. The friends met at the campus, she said, but Conyers did not show up.

Lewis said the friends then went to Conyers' apartment where they found that his identification card, debit card and some clothing were gone, while his car, phone, computer and other items were left behind.

John Conyers, a Democrat who represents Michigan's 13th congressional district and is the longest-serving current member in Congress, had asked for privacy on Thursday while his family worked through what he called "this situation of uncertainty."

Houston police led the investigation into Conyers' disappearance and the Federal Bureau of Investigation and the Secret Service helped in the search.

A private search and rescue group, Texas Equusearch, is also involved in the search.

(Reporting by Laila Kearney; Editing by Daniel Wallis and Bill Trott)