Pol Col Thitisan "Joe Ferrari" Utthanaphon has admitted to wrapping a plastic bag over a drug suspect's head but claimed he had no intention in causing the suspect's death.
The former Muang Nakhon Sawan police chief testified before the Central Criminal Court for Corruption and Misconduct Cases on Wednesday during a court trial.
The ex-superintendent was one of seven defendants present in court.
They said that on Aug 4 last year they were posing as customers to arrest the suspect, Jeerapong Thanapat, and his wife.
Later they interrogated them back at the police station.
Pol Col Thitisan said he used the plastic bag to intimidate the suspect and did not wrap it too tightly.
The next hearing is on March 16.
Leaked video footage of the interrogation sparked public outrage.