The officer who shot and killed a 73-year-old retired librarian during a citizen academy "shoot/don't shoot" class resigned from his previous department shortly after two excessive force complaints were filed against him, according to records released Thursday.

One of the 2013 complaints filed with the Miramar Police Department against Officer Lee Coel was mostly unfounded, but a second one clearly showed that Coel pulled a handcuffed man from the back of his cruiser by the ankles and caused him to land hard on the pavement.

The man, Stennette Simpson, had been accused of marijuana possession. He told investigators that he had fallen asleep.

"By the time I was being pulled, I woke up and screaming at officer, 'What are you doing, officer? What are you doing, officer? What are you doing?" he told investigators. "By the time I know, he's pulling me, I hit my head coming down and hit my back on the floor."

Coel, 28, resigned from the Miramar department shortly after the complaint, following about 14 months on the job. He was hired about a year later by the Punta Gorda Police Department, where earlier this week he shot Mary Knowlton during an exercise designed to show citizens the split-second decisions police officers must make. Such exercises don't normally use live ammunition.

Punta Gorda Chief Tom Lewis said Thursday he is taking "full responsibility" for the shooting, which he witnessed Tuesday night. He expected the Florida Department of Law Enforcement to finish its investigation in about two to four weeks. Coel is on administrative leave.

In the other Miramar excessive force claim, suspect Benson Kinney claimed he almost suffocated in Coel's police car because the officer turned the heater on high and refused to roll down the windows. Kinney said he was handled roughly once at a police station and that Coel drove at excessively high rates of speed.

Investigators concluded that the allegations were unfounded except for the speeding, which they said topped out at 102 mph and could have placed both men in danger.

Coel, a native of Cooper City, Florida, played football at Simpson College in Iowa and intended to be a veterinarian, according to Miramar personnel files. But not long after graduating with a biology degree in 2010, Coel shifted gears and decided to become a police officer. He specifically hoped to become a K-9 officer.

During his training, other Miramar officers said Coel had "very strong command presence" and was able to take charge of crime scenes and arrests. One nagging problem was that Coel had a tendency to drive too fast and get lost on the way to calls, sometimes placing other officers waiting for him in danger, according to the records.

"Trainee gets turned around easily. This has been a major struggle," one superior officer wrote. "He is letting the stress get to him, which is causing him to make more mistakes."

A Punta Gorda lawyer said Wednesday that Coel shouldn't have been on the Punta Gorda force. Scott Weinberg is representing a man who said he was mauled by Coel's K-9 during an arrest in November. Weinberg took the man's case in June, and that's when he viewed Coel's dashcam video of the arrest and informed local media about the case.

"I told everyone that this officer was dangerous and he needed to be fired," said Weinberg, who didn't identify his client. "If he had been fired like he should have been when he ordered that dog to maul my client for a minute and 47 seconds, then this wouldn't have happened."