Former New England Patriots linebacker Jerod Mayo posted an emotional message on Instagram Monday, a day after his pet Knox was found dead in a dog trainer's home after being missing for weeks.

Knox went missing while out with the dog trainer in Wrentham in late June. On Sunday, the Rhode Island SPCA found 5-year-old Knox's dead body inside the home of dog trainer Ameila Ferreira, who lives in the Edgewood section of Cranston.

Now, Ferreira is being charged by the Cranston Police Department with one count of obstruction for concealing evidence relevant to the investigation, the RISPCA said.

Ferreira could face animal cruelty charges pending results of a necropsy, the RISPCA said. The cause of Knox's death is currently unknown.

The RISPCA did not release many details of the investigation in a news statement, but Mayo wrote that Knox's body was discovered in a trash bag.

Mayo wrote on Instagram that "the answers we prayed for regarding Knox aren't ones we were ready to face."

"Knox has passed and his BODY WAS FOUND IN THE HOME OF THE OFFLEASH TRAINER," he wrote. "IT's disgusting and inhumane that a company full of 'dog lovers' would hide a family pet IN A CLOSET FOR TWO MONTHS and compulsively lie and send us on a wild goose hunt and our kids on an emotional rollercoaster."

Knox went missing in late June while on a walk with a trainer at Joe's Rock, a conservation area located off 1500 West St. in Wrentham. Police said Knox and another dog were being walked when the trainer had to focus on the other dog. Knox "simply vanished," police said in a statement at the time.

"Staging him running away, him being stolen, even him drowning having us knocking on doors sending us false leads as we searched two states," Mayo wrote. "We've hired scuba teams, private investigators, lawyers and more when they knew they HAD HIM IN THEIR HOME IN A TRASH BAG tucked away the whole two months."

Mayo wrote that Knox was like a child to the family.

"It hurts to have to accept that our beloved Knox was thought of as trash as they saw our family hurting," he wrote.

Mayo wrote that his family thanked everyone who helped with the search for Knox.