As Bill Cosby's retrial on sexual assault charges approaches, Montgomery County prosecutors are seeking to introduce testimony from more women who have accused Cosby of sexual misconduct—18 more than the court allowed at his first trial, to be exact.

The Montgomery County District Attorney's Office filed a motion Thursday in the Montgomery County Court of Common Pleas, arguing that although the criminal charges Cosby is facing relate only to allegations by one woman—Andrea Constand—prosecutors should be allowed to present testimony of other women who have accused Cosby of sexually assaulting them. The motion included accounts from 19 women the prosecutors hope to call as witnesses.

At Cosby's first criminal trial, in June, Judge Steven T. O'Neill allowed testimony from just one prior bad acts witness, who alleges that Cosby drugged and sexually assaulted her in 1996. Prosecutors had asked the court to allow 13 prior bad acts witnesses at the first trial.

Cosby's first trial ended in a mistrial, after a jury from Pittsburgh deliberated for five days and was unable to reach a verdict. His retrial is set to begin April 2. He is facing three charges of aggravated indecent assault, based on Constand's allegations that he drugged and sexually assaulted her at his Cheltenham home in 2004.

In their most recent motion, prosecutors argued that the accounts of other women are relevant because they show a common scheme to each alleged assault, and the absence of mistake. In addition, the motion said, the evidence is admissible under the doctrine of chances, also known as the doctrine of objective improbability.

“Under this non-character-based theory of logical relevance, as the number of victims reporting similar drug-induced sexual assaults by defendant increases, so does the objective improbability that defendant mistakenly assessed each victim's level of consciousness when engaging in sexual contact with her,” the district attorney's motion said.

According to the motion, the District Attorney's Office has investigated more than 50 allegations against Cosby of drug-facilitated sexual assault. Dozens of women have made those accusations publicly, and several have filed civil lawsuits against Cosby, some of which are ongoing.

The 19 women the district attorney hopes to call as witnesses, including the six new accusers, have alleged that Cosby assaulted them between 1965 and 1996. The most recent allegations are from the woman who testified at the first trial. Most of the alleged assaults took place in the 1970s and 1980s.

Montgomery County District Attorney Kevin Steele announced the charges against Cosby in December 2015, just before the 12-year statute of limitations on Constand's allegations was set to expire. Constand originally went to law enforcement in 2005, but then-Montgomery County District Attorney Bruce Castor Jr. declined to prosecute Cosby. Constand brought a civil suit against Cosby, which ended in a confidential settlement in 2006.

Constand and Castor are currently embroiled in their own civil litigation. Constand has sued Castor in federal court, alleging he defamed her in his statements about the 2005 investigation. Castor has sued Constand in Philadelphia court, alleging that she only brought the defamation claims to destroy Castor's political career.

Andrew Wyatt, a spokesman for Cosby's legal team, declined to comment on the motion.