Fresno Police Chief Jerry Dyer takes the stand in Keith Foster trial

FRESNO, Calif. (KFSN) -- Testimony in the trial of former Fresno Deputy Police Chief Keith Foster wrapped up on Wednesday. The final witness was Police Chief Jerry Dyer.

Chief Dyer dyer cast doubt on Foster's claim to be doing an independent investigation of Fresno's drug problem. Dyer testified he felt betrayed when he was told his deputy and long time friend was arrested on drug trafficking charges. On leaving the courthouse Dyer explained his feelings.

"Whether the allegations turn out to be true or not, the fact is, this investigation occurred, and Keith was arrested and as a result I felt a sense of betrayal," said Dyer.

Foster was arrested by the FBI in March of 2015. He's accused of conspiring to deal heroin, marijuana and the opiate pill Oxycodone, commonly known as Oxycontin. On the stand, Dyer testified he had the utmost trust in Foster during the years they worked together. He said the allegations against his former deputy chief and friend were shocking, and damaged the image of his department.

"The thing that is the most important to me is maintaining the trust of our citizens of the police department and of me, their police chief," said Dyer.

Throughout the trial Fosters attorney has tried to show he was involved in some kind of undercover operation to get to the bottom of Fresno's drug problem. On the stand, Dyer acknowledged he had assigned Foster to look into the problem of drug overdose deaths in Fresno but never discussed any kind of independent investigation into drug dealing.