An auto-inflating life vest worn in June by a man who drowned following a Finger Lake canoe accident didn't inflate because it wasn't "properly armed" and was "inoperable," according to Alaska State Troopers.

Those conclusions were part of an Alaska Department of Public Safety incident report on the June 19 death of 67-year-old Edgar Curtis. In the report, obtained by KTVA through a public-records request, troopers say the accidental drowning was "due to the failure to arm the auto-inflatable life vest."

Troopers say Edgar Curtis and his 30-year-old son, Gary, had been out for a canoe ride on Finger Lake. In the report, Gary Curtis says the wake from a boat tipped the canoe, tossing the men into the water. According to the report medics on scene reported that both men were wearing inflatable vests, but neither inflated.

The report states Gary was trying to help his father while yelling for help. He says he saw the boat "slow down, turn around near them, pause for a short time, then turn and speed away without rendering any aid." The report says that Gary Curtis "was able to tread water and attempted to hold Edgar above water but soon lost grip and Edgar submerged."

Gary made it to shore. Edgar's body was later found in the water with his inflatable life vest still on but not inflated.

The incident report says the vests worn by both men didn't show any damage or sign of malfunction.

"Neither of the inflatable vests had been properly armed," troopers wrote. "The air cartridges had never been properly connected making the life vest inoperable."

In the wake of the drowning, Alaska Office of Boating Safety staff offered some recommendations on maintaining auto-inflating vests, saying their inflation cartridges need to be routinely replaced and tightly secured.

Gary later told investigators the vests the men were wearing were purchased new and were about a year old. The report says they had just been opened that day.

Investigators say a further check of the vest Gary wore revealed "the arming cylinder for the device was never removed from the shipping plastic and installed in the arming device, rendering the automatic inflation feature inoperative."

A label on Edgar's vest, the report said, warned that "(w)eak or non-swimmers should not use this device unless worn inflated."

In the incident narrative, investigators wrote that "Gary can swim but his father cannot." Family members told KTVA Edgar could swim, but not very well.

The report also states that investigators interviewed someone with a boat that matched the description Gary Curtis provided. That person said he was on the lake that day with his family, but said he never saw a canoe and didn't know anything had happened until he saw emergency vehicles.