Until final autopsy and toxicology results come back, Manuel Ricardo Cuesta's exact cause of death remains unknown.
Cuesta died on Jan. 26 after he collapsed while running in the South Texas Sizzler 5K race in Harlingen.
A doctor and nurse at the scene tried to administer first aid until paramedics arrived.
An ambulance rushed Cuesta to the Valley Baptist Medical Center where he died.
Investigators said that the preliminary autopsy results could not rule out an exact cause of death.
Cuesta leaves behind a wife and a 7-year-old boy who were both at the race.
The 37-year-old was running with a group of Alta Vista Rehab Center co-workers.
They have set up a Chase bank account for Cuesta TMs family.
Chase Bank Savings Acct #: 2926726980Acct Name: Norma Guerrero for Manuel Cuesta