Investigators were at a Clarksburg townhouse Wednesday to continue their inquiry into the death of Nathan Jones, who was pepper sprayed by Montgomery County police Monday after what a neighbor said was erratic and threatening behavior in the neighborhood.

Jones, 39, lived on Tailor Shop Place in a home run by Family Services Inc., which police said houses individuals with mental and intellectual disabilities.

Police said that Jones threatened two housemates with a hammer and knife Monday and resisted when they sought to arrest him on a charge of first-degree assault. Police would not describe the nature of Jones’s resistance but said officers have the discretion to determine how to most safely subdue a person.

The Montgomery police directive on the use of force outlines four levels: communication/verbal control; physical force using an officer's body; the use of “protective instruments,” including batons and pepper spray; and deadly force, including firearms.

But those options are “not predicated on a strict hierarchical sequence,” according to the policy. It is “the immediate potential for death or serious physical injury to the officer or innocent bystanders and/or victims upon which officers should base their decision to use force of any level,” according to the policy.

Given the knife and hammer threats, “you can see why officers would be a little unsure of this gentleman,” said Officer Britta Thomas, a police spokeswoman.

After Jones was sprayed and taken into custody, fire and rescue service responders worked to “decontaminate” him for about 10 minutes, authorities said, then left. “The patient had to be stable and in no need of any type of medical treatment,” Assistant Fire Chief Scott Graham said.

But within minutes, Jones began to worsen and then stopped breathing. The fire and rescue team was called back, arriving minutes later as police were performing CPR, Graham said, adding that Jones was in cardiac arrest. Responders continued treatment and took Jones to a hospital, Graham said. Jones was later pronounced dead.

Graham said the responders acted properly.

Jones’s Clarksburg neighbors had seen a recent change in his behavior and have concerns about the home, according to Jill Pelaez, who lives next door with her husband and young children. Last Friday, as she went out for a run, she saw Jones smiling and waving urgently, “like he was in a manic mode,” she said. Later that day, a census worker with business at Jones’s residence told Pelaez that Jones threatened her, Pelaez said.

“What bothers me is he was acting so strange the week before, and it doesn’t seem like anything was done until he lost it,” she said, adding that her mother also saw Jones yelling at a recycling truck recently. “It’s sad,” she said. “If they would have intervened when the behavior started to change, maybe they could have prevented it.”

Thom Harr, executive director of Family Services, said he could not speak specifically about Jones. “We certainly do monitor,” he said. “When we see changes, we always try to address it.”

He noted that it was his staff that called police on Monday. “It’s independent living. We do have contact with people, and we monitor and react,” he said.

Jennifer Jenkins contributed to this report.