Wichita ? The man charged with being the BTK serial killer was an unfair boss who created a hostile working environment, according to a co-worker who reported to Dennis Rader for more than six years.

“Dennis was a very difficult person to get along with,” said Mary Capps, who worked with Rader as a compliance officer in Park City. “It was his way every time.”

Capps, a 45-year-old single mother, said Rader was a rigid stickler for detail, never gave her compliments and discriminated against her because she is a woman. She is filing complaints with state and federal officials claiming Rader created a hostile work environment and city officials did nothing to fix it.

Rader, 60, is charged with 10 counts of first-degree murder for a series of killings in the Wichita area between 1974 and 1991. The killings are attributed to the BTK killer, who coined his own nickname, meaning “bind, torture, kill.”

Rader is scheduled to appear in court April 19 for his preliminary hearing. His public defenders couldn’t be reached for comment regarding Capps’ charges.

Capps’ lawyer, Ted Wagner, said he was requesting records from Park City about tranquilizers used in animal control, looking to see whether there is a connection to a series of illnesses Capps said she suffered while working with Rader.

Capps told The Wichita Eagle that beginning in 2001, she started to have muscle spasms. She said she had trouble concentrating and sometimes missed work. She said the symptoms ended Feb. 24, a day before police arrested Rader.

“I think the significance is they haven’t come back. She is not experiencing any additional symptoms,” Wagner said, acknowledging that the symptoms also could have been due to work-related stress.

Dee Stuart, mayor-elect of Park City, said Capps complained to her several times about Rader and “his obsessive fascination with detail, that everything had to be … perfect as he saw it.” Stuart said Capps also was frustrated that city policy required her to file any complaints about Rader with Rader.

Capps and Wagner said she filed four formal complaints against Rader, the latest coming earlier this year. Wagner said one complaint has been filed with the federal Equal Employment Opportunity Commission, and another is being prepared for the Kansas Human Rights Commission. She may file a civil lawsuit.

While Capps had little good to say about Rader’s office demeanor, she did say he was a good family man and when he talked about his family, “his voice would change. You could see love and concern.”