After losing his iPhone at a reggae concert on Dec. 28, San Diego resident Kenneth Schmidgall used the Find My iPhone app to track down the device.
Schmidgall told HuffingtonPost.com: "I wasn't looking for a confrontation. I just wanted the phone back. I saw it stationary at a bike shop in Encinitas, but then it started moving around, and I got the idea that whoever had it was trying to sell it near the beach."
The app led Schmidgall and his roommate Greg Torkelson to a man riding his bicycle near Torrey Pines State Beach.
Schmidgall told KGTV-TV: "I saw the gentleman on the bike and we followed it and kept tracking it and every time it would stop, the guy on the bike would stop."
Schmidgall and the alleged thief finally had a fight for the device on the beach, which was recorded by Torkelson with his camera (video below).
Schmidgall recalled: "He said, 'Do you want your cellphone?' and pulled it out of the pocket like he was going to throw it in the ocean."
Torkelson pepper sprayed the man, but he kept going even after being sprayed.
The fight continued until an off-duty police officer, who was walking nearby, held the alleged thief on the sand until police arrived.
Schmidgall was finally reunited with his iPhone and said: "I had to wait until I was home to unlock it. The battery was almost dead. I'm surprised the guy didn't ditch it."
"I don't think everyone should get in a fight for their phone, but I want people to know that if it's taken, there's something they can do to get it back."