POLK COUNTY, Fla. ? A Polk County Fire Rescue paramedic was arrested on Thursday in connection to a sexual relationship with a minor.

Authorities said 49-year-old Warren "Nick" Nichols had an ongoing sexual relationship with a 17-year-old girl for a month.

Nichols twin brother, William "Bill" Nichols, was also arrested because investigators said he knew about the relationship and didn't report it. He had been a Polk County sheriff lieutenant since 1988 until he resigned upon his arrest.

Nick Nichols is charged with 30 counts of unlawful sex with certain minors and is being held without bond until his first appearance on Friday. He is also charged with domestic violence battery in connection to an altercation between him and the 17-year-old's mother, a news release said.

The teen's mother was charged with pointing a handgun at the girl during the argument.

Bill Nichols is charged with failure to report suspected child abuse. He was released on $2,500 bond.