ALAMO - Authorities are working to identify a man's body found floating in a canal near the Donna reservoir Monday evening.

A nearby resident found the man's body about 7:30 p.m. Monday in the canal near Border Road, said Capt. John Montemayor of the Hidalgo County Sheriff's Office.

Deputies are checking the man's fingerprints and other aspects to determine his identity, Montemayor said. Investigators believe he was between 24 and 30 years old.

A welfare concern was reported to the Alamo Police Department about 6 p.m. Monday that said a man had not been seen since Saturday. The estimated decomposition of the body found in the canal - between two and five days - suggests the man reported missing could be the same person found in the canal, Montemayor said.

"You could tell that he's been in the water for several days," Montemayor said. "We're treating it as a homicide, but the cause of death is undetermined right now,"

Preliminary autopsy results expected to be released Tuesday afternoon will likely identify what caused the man's death.