Diaz was putting up crime scene tape at a stabbing at Stone Pine Lane near Blazey Drive when he suffered a medical crisis.
He died later at the hospital.
"Deputy Diaz served his community with honor and distinction," said Gonzalez. "The entire Harris County Sheriff's Office family is grieved by the tragic loss of our brother."
Diaz's funeral was held at the Champions Forest Baptist Church Jersey Village Campus.
Deputy Diaz is survived by his wife and 7-year-old daughter.
Diaz joined the sheriff's department in 2009 as a detention officer and graduated from the academy in 2018.