The girl, now 15, told investigators she and Johnson had sex several times in his SUV and in his home between June and November last year, according to the complaint.
The girl told Johnson in July that she was pregnant, the complaint says. Johnson told the girl to have an abortion, according to the complaint.
Johnson has been suspended with pay from the Milwaukee Fire Department, said Tiffany Wynn, the department's spokeswoman.
Written by The Milwaukee Journal Sentinel