HILLSBOROUGH COUNTY, Fla. (WFLA) — A man accused of shooting and killing his mother on her birthday was arrested Wednesday.

The Hillsborough County Sheriff’s Office said it was called to the 1600 block of Colwood Drive in Keystone around 7 p.m. Tuesday to do a welfare check on 78-year-old Joanne Turrell.

When deputies entered the home, they found Turrell dead and covered with a blanket.

The sheriff’s office said Turrell’s son, 53-year-old Douglas Turrell was found in a locked bedroom with a gun near him. They said Douglas Turrell lived at the home with his mother.

Investigators determined Joanne Turrell had been shot and killed. Detectives said they arrested Douglas Turrell on a second-degree murder charge.

“Our heart breaks for the friends and family of this woman whose life was not only tragically ended but done so at the hands of her son,” said Sheriff Chad Chronister. “Joanne Turrell was celebrating her 78th birthday. A time that should have been filled with joy and beautiful memories. Instead, we are now trying to piece together what resulted in it ending in such heartbreak.”

The investigation is ongoing. No other information was immediately available.