Police in Gardiner and Richmond have ended their search for incendiary devices reportedly placed in the woods by a man accused of killing his father, but authorities continue to urge those who roam into the woods to use caution.

Leroy Smith III, 24, told police he placed the devices in the woods to alert him to foot traffic so he could identify safe places to grow marijuana. Smith last week was charged with murdering his father, 56-year-old Leroy Smith Jr., with whom he shared an apartment on Cannard Street in South Gardiner.

“We’ve found no evidence that these devices exist, and in all likelihood this has probably been a hoax,” Gardiner Police Chief James Toman said. “That said, I cannot guarantee they’re not real.”

Police on Thursday scoured the woods by air and train tracks looking for a campsite and the explosive devices, which police described as paper tubes, such as toilet paper rolls, wrapped in duct tape with some filament and filled with black gunpowder. Local police, joined by Maine State Police units with three bomb-sniffing dogs, searched the woods on foot Tuesday and Wednesday before Thursday’s search.

Toman said if any of the devices are in the woods, they probably would not work; but even if they did work, they probably would not explode.

“These devices weren’t meant to harm anybody,” Toman said. “They were meant to be an alerting system to Smith. If they were to work, and even that is a big question, they were meant to catch on fire so he could see where people go.”

Smith was known to take long walks in the area, including the woods, authorities said. Police also said Smith told them he was an avid hiker and was interested in survival-type gear. Richmond Police Chief Scott MacMaster said they think Smith would walk up to 15 miles, often overnight.

Police in both communities have alerted residents by fliers and telephone. Smith told police he planted more than 20 of the devices.

“We have responded to a few incidents and checked on areas that citizens have called in to us,” MacMaster said. “Nothing was found. We feel that based on the information provided to us about the numerous amount, that we would have at least found one by now.”

Both chiefs urged those walking in the woods to watch for the devices. MacMaster said if a device are spotted, hikers should mark the spot with a GPS tag on their smartphones or find some other way of marking the location so authorities can find it easily.

“Be careful and watch out for anything that looks suspicious or out of place,” MacMaster said.

Toman offered hikers other general safety tips, such as making sure they have plenty of water and fully charged cellphones before venturing into the woods.

“Whenever you’re out and about, always try to have a partner or let someone know where you’re going and when you’ll be back,” Toman said. “Always err on the side of caution.”

Craig Crosby — 621-5642 | ccrosby@centralmaine.com | Twitter: @CraigCrosby4