Critical Thinking Puzzle

A rather silly car thief stole, without knowing it, the car of the chief of police. The police immediately started an investigation and based on witness depositions, four suspects were arrested that were seen near the car at the time of the crime.

Because the chief of police took the case very seriously, he decided to examine the suspects personally and use the new lie detector of the police station. Each suspect gave three statements during the examinations, which are listed below:

Suspect A:

“In high school, I was in the same class as suspect C.”
“Suspect B has no driving license.”
“The thief didn’t know that it was the car of the chief of police.”
Suspect B:

“Suspect C is the guilty one.”
“Suspect A is not guilty.”
“I never sat behind the wheel of a car.”
Suspect C:

“I never met suspect A until today.”
“Suspect B is innocent.”
“Suspect D is the guilty one.”
Suspect D:

“Suspect C is innocent.”
“I didn’t do it.”
“Suspect A is the guilty one.”
With so many contradicting statements, the chief of police lost track. To make things worse, it appeared that the lie detector did not quite work yet as it should, because the machine only reported that exactly four of the twelve statements were true, but not which ones.

Who is the car thief ?