ST. PETERSBURG — The investigation into the deadly scuba tank blast that killed Russell Vanhorn II on Sunday continues to move forward this week.
Investigators had to go back to the scene of the explosion Tuesday to find a key piece of evidence left in the rubble. They're also retracing the tank's history and arranging for local and federal experts to test it.
St. Petersburg police are also exploring this angle: Was any scuba gear involved in the explosion stolen?
"We're looking at the possibility that some … stolen equipment may have turned up here," said police spokesman Mike Puetz.
Vanhorn was accused of stealing a dive reel from his former employer, Scuba West in Hudson, according to court records. In August he was charged with misdemeanor petty theft.
According to a Pasco County Sheriff's Office report, a Scuba West employee said she saw a dive reel inside Vanhorn's lunch bag in April. Cave divers use the reels so they won't get lost.
She determined Vanhorn hadn't paid for the reel, the report said. Owner Jeff Tobey said he fired Vanhorn, and received this e-mail from him: "I wish I could turn back time and stop myself from taking the reel."
The shop reported more equipment missing: seven tanks, four dive lights, a side-mounted buoyancy control device and a regulator. In July a client reported seeing Vanhorn with the shop's tanks at Eagle Nest, a cave diving spot in Hernando County.
But there was no evidence that Vanhorn took anything but the dive reel, according to the State Attorney's Office. He wasn't arrested but was sent a summons ordering him to appear in court next month.
Vanhorn, 23, is a veteran of the Iraq war who learned to scuba dive while he was in the Marine Corps. He was preparing to go diving with two others early Sunday morning when police said the tank he was carrying exploded, destroying the condo at 5865 37th Ave. No one else was injured.
When investigators reassembled the tank, they discovered that the diving regulator was missing. That controls the pressure of the gases that divers inhale. They returned to the blast site on Tuesday and found it in the rubble.
Investigators still believe the blast was accidental. But as a precaution the tank will be tested at the Pinellas County Forensic Lab for signs of anything combustible.
"It's to rule out the possibility that a foreign substance got into the tank," Puetz said. "There's no allegations that anyone put anything volatile on there."
Then the tank will be given to the U.S. Transportation Department, which regulates the devices, to determine exactly what went wrong.
Police are also tracking down the history of the tank: who filled, serviced and inspected it.
Investigators ask anyone who has gone diving with Vanhorn or has any firsthand information — and not just theories — about the blast to call police at (727) 893-7780. Anonymous tipsters can call (727) 892-5000 or text police at (727) 420-8911.
Times staff writer Molly Moorhead contributed to this report.