ST. PETERSBURG, Fla. — Thomas Mosley, the St. Petersburg man accused of killing his 2-year-old son and the toddler’s mother, has pleaded not guilty, according to court documents.

Mosley is charged with two counts of first-degree murder in connection with the deaths of Taylen Mosley and Pashun Jeffery, which happened after the family celebrated the defendant’s birthday in late March.

Investigators said Mosley stabbed Jeffery more than 100 times. After the toddler’s mother was found dead in her St. Pete apartment, 2-year-old Taylen was reported missing. The same night, Mosley appeared at his mother’s house with cuts along his arms and hands, according to the arrest report. 

Authorities later found Taylen’s body inside an alligator’s mouth in Lake Maggiore, more than 10 miles from his home. Officials listed the toddler’s cause of death as drowning.

Court documents show that prosecutors plan to seek the death penalty against Mosley. Prosecutors have laid out numerous reasons for seeking the death penalty — arguing the crime was especially cruel, the victim was younger than 12 years old and was more vulnerable because his accused killer had authority over him as his parent, court filings said.  

Mosley is scheduled to appear in court on Monday morning for a pretrial hearing.