(CNN) A New York police detective who testified in a probable cause hearing in the case of slain Barnard College student Tessa Majors is facing lawsuits that allege he falsified evidence, made false accusations and forcibly searched residences without warrants, court documents show.

New York Police Department Commissioner Dermot Shea said Detective Wilfredo Acevedo has never been found to have made a single false statement or falsely arrested anyone and touted his exemplary record of service.

The president of the union that represents active and former NYPD detectives called the lawsuits a "commonly used strategy employed by defense attorneys" to undermine investigations.

The cases were highlighted by the Legal Aid Society in an email to CNN. Hannah Kaplan, an attorney with the Legal Aid Society, represents a 13-year-old boy who has been arrested and charged in connection with the killing earlier this month.

CNN has not been able to reach Acevedo for comment.

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