SAN FRANCISCO, California (CNN) -- A fourth person was arrested Tuesday in the case of a kidnapped teen who escaped captivity wearing only boxer shorts and a shackle on his ankle, police said.
Police say the teen was able to escape his captors and walk into this Tracy, California, fitness center.
Anthony Waiters, 29, was arrested Tuesday and charged with torture, false imprisonment and other charges, according to police in Tracy, California, located about 70 miles east of San Francisco.
The teen escaped a year of captivity December 1 and walked into a fitness center in Tracy. He was bruised and battered, wearing only boxer shorts and with his bloody ankle shackled, police said.
Police have arrested Caren Ramirez, 43, Kelly Layne Lau, 30, and her husband, Michael Luther Schumacher, 34, in the case. It is unclear how Waiters is related to other three alleged abusers of the 16-year-old boy.
Authorities said the teen was shackled in the home of Lau and Schumacher. During his captivity, the teen was tortured with a bat, knife and belt, according to court documents.
Police said the home where the teen was held captive was about 500 feet from the fitness center, and he apparently was able to get over a wall and onto the center's property. Lea Leonardo, assistant manager of the center, said the boy came into the facility and begged her to hide him.
"He was very dirty. He looked very young, very skinny and was wearing nothing but men's oversized boxers," Leonardo told CNN. "He was terrified."
The boy initially had been removed from his parents' custody in Sacramento, California, by social workers because of abuse and was placed with Ramirez, a family friend. The teen was sent to a group home after Ramirez was charged with felony abuse against him, but escaped the group home about 18 months ago, police said.
Authorities said they believed the boy returned to Ramirez, but aren't sure when or why. Authorities also did not say how the teen got from Ramirez's home to the home in Tracy where he was allegedly abused.
A judge has imposed a gag order in the case.
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