MYAKKA CITY, Fla.  —  A 20-year-old man was arrested in the slayings of his parents, younger brother and elderly grandmother, whose bodies were found in their home Sunday, authorities said.

Richard Edgar Henderson Jr. was arrested Sunday evening and was being charged with four counts of murder, Manatee County sheriff's officials said. He was booked in jail with no bond.

The bodies of his parents Richard Henderson Sr., 48, and Jeaneane Henderson, 42, grandmother June Henderson, 82, and 11-year-old brother Jake Henderson were found Sunday about 12:30 p.m., the sheriff's office said.

Authorities said the four were beaten to death with a pipe in their house Thanksgiving evening. Sheriff Charlie Wells said Henderson recounted the slayings in an interview with detectives Sunday night.

The medical examiner was working to determine an official cause of death.

"This is not real," neighbor Annette Segura, 60, told the Sarasota Herald-Tribune. "How can you have your neighbors wiped out? I hurt for them."

Henderson was arrested shortly before 7 p.m. Sunday walking along U.S. 301 in Palmetto, the sheriff's office said.

He was seen Sunday morning at the family home on the Hardee County line. He later abandoned a van in nearby Wauchula, the sheriff's office said.

The sheriff's office didn't return messages seeking additional details Sunday. It was not immediately known if Henderson had an attorney.

Myakka City is about 45 miles southeast of Tampa.