CAMBRIDGE, Mass. -- A state police trooper pleaded not guilty Friday to charges he sexually assaulted a woman while on duty.

NewsCenter 5's Pam Cross reported that Daniel Grant, 42, was indicted by a grand jury last week. He was charged with three counts of rape Friday.

In court Friday, prosecutor Elizabeth Dunigan told a sordid story. On Jan. 20, Grant allegedly stopped a car with a man and a woman inside. Prosecutors said Grant ran the license plate and found warrants for the male passenger. The trooper then allegedly gave the man a small amount of money and sent him away.

"(Grant allegedly told her) that was a bad guy that she was with. He said to her, 'How are you going to thank me? How are you going to repay me?'" Dunigan said.

Grant then allegedly showed the woman a bag with white powder and said, "This could be yours."

Grant then told the woman to follow him to a deserted state-owned building behind the Royal Sonesta Hotel in Cambridge on Memorial Drive, prosecutors said. The woman said she was raped at that location three times.

After the alleged attack, the woman went home and was brought to the hospital by her husband and father. A rape kit was not collected.

Grant's attorney said the trooper maintains his innocence. Grant, a married father of two with 18 years on the force, has been placed on unpaid leave.

Grant was held on $2,500 cash bail.