Jonathan Flores, 32, of northwest Harris County left his home on Sunday morning, his girlfriend said.
Five days later, his friend Christian Briones discovered his body sticking out of a rooftop A/C unit at a business park of the West Sam Houston Parkway near West Road.
Briones said it appeared as if Flores had been electrocuted.
"His body was just laying inside the thing he was trying to take something apart," Briones said.
Based on prior conversations with him, his girlfriend said she suspected he could be somewhere in the general vicinity of the business park and said she requested detectives look there when she filed a missing person's report on Wednesday.
"They didn't look. They didn't want to look, and I told them," Briones said.
The Harris County Sheriff's Office hasn't returned ABC Houston affiliate KTRK's emails seeking information about the case.
Briones said he took it upon himself to search for his friend and found his bike abandoned about a half mile from the business park.
"That's when I knew something wasn't right," he said.
When he got to the business park, he said he was immediately overcome by a strange smell.
"There's no way for them to not be able to smell that," he said.
Briones said he climbed a ladder to reach the roof, which is where he discovered his friend's decomposing body.
He can only speculate as to why Flores might have been there.
"I just don't know what the hell was going through his head at that time," he said.
What he does know is that he's lost a dear friend who he says at times was more like a brother.
"I was living just across the street from him. Showed up, fixed my A/C right away. Didn't ask for anything. That was just my friend," Briones said.