Martin Shkreli Paul Taggart | Bloomberg | Getty Images

The pharmaceutical company boss under fire from Hillary Clinton and many others for jacking up the price of the drug Daraprim 5,500 percent overnight allegedly engaged previously in a bizarre campaign of "harassment" of a former employee and his immediate family, according to court documents. Drug boss Martin Shkreli, 32, also allegedly gained access to social media accounts belonging to that ex-employee, and contacted him and his relatives directly, including his teenage son and wife, as he accused the worker of defrauding Shkreli's then-pharma company, Retrophin. "Your husband had stolen $1.6 million from me and I will get it back. I will go to any length necessary to get it back," Shkreli allegedly wrote the wife of former Retrophin employee Timothy Pierotti in a January 2013 letter, according to court documents.

"Your pathetic excuse of a husband needs to get a real job that does not depend on fraud to succeed ... I hope to see you and your four children homeless and will do whatever I can to assure this," Shkreli allegedly wrote. Read MoreRead the affidavit claiming harassment by Martin Shkreli and see the related documents here.

Police in New Jersey were contacted about the alleged harassment as it escalated around Christmas, Retrophin settled a lawsuit against the ex-worker out of court, confidentially, in early 2014 after the employee's lawyer asked a New York judge to order Shkreli's computers to be analyzed on the heels of the allegations.

Retrophin's board later move to replace Shkreli as CEO, and he resigned his positions. Retrophin is now suing him for $65 million in a case where he is accused of acting against the interests of the company. Shkreli, through a spokesman, declined to comment for this story. Pierotti's lawyer declined to comment, citing a confidentiality agreement. A Retrophin spokesman, when asked for comment, said: "Retrophin's claims regarding Mr. Shkreli are detailed in the company's lawsuit against him. The company's leadership is focused on running and growing the business and will make its arguments on this matter in court or in arbitration, as appropriate. The Pierotti litigation was brought and settled under Mr. Shkreli's tenure, and we have no further comment on the matter." Shkreli made headlines this week when it was revealed that his current company Turing Pharmaceuticals, had hiked the price of Daraprim from $13.50 to $750 per pill after Turing bought the drug, which is used to treat a parasitic infection, in August. The move, which Shkreli has defended as necessary for Turing to be profitable and to fund research for a replacement drug, drew widespread criticism, with Clinton calling the move "outrageous." Clinton's comment, and her vow to introduce a plan to control drug prices overall, sent biotech stocks plummeting Monday. Shkreli, a former hedge fund manager, had been fired from Retrophin, which he founded, last year. In August, the company sued him in Manhattan federal court, for "repeatedly breaching his duty of loyalty to Retrophin," by allegedly using his control of Retrophin to "enrich himself and to pay off claims of [his prior hedge fund's] investors (who he had defrauded)," Retrophin claimed in its suit. "Shkreli was the paradigm faithless servant," Retrophin charged in its suit, which is seeking $65 million in damages from its founder. Shkreli has denied Retrophin's claims, and has asked that the dispute be settled in arbitration. He told The New York Times that Retrophin owes him at least $25 million in severance, and that "they are sort of concocting this wild and crazy and unlikely story to swindle me out of the money."

But before that suit, Retrophin, with Shkreli at the helm in 2013, sued Pierotti in New York state court seeking the recovery of 350,000 shares of Retrophin stock "that was taken by the Defendant," the company said in court papers. Retrophin claimed it had facilitated a purchase of its stock at a deep discount by Pierotti with a promise by him that he would work for the company to develop revenue-generating acquisitions. Retrophin accused Pierotti of abruptly reneging on that promise, and then "absconding with the stock," which then was worth at least $3 million, or about 7,000 times the $400 that he paid for the shares. Pierotti's lawyers moved to dismiss the claims on a number of grounds, but the case continued through 2013. According to court documents filed by Pierotti and his lawyer, Shkreli's harassment of the former Retrophin employee escalated in late 2013. "I submit this affidavit to provide first-hand evidence of the repetitive harassment that Shkreli has inflicted on not only me, but on my wife, teenage children, elderly father, as well as other family members," Pierotti wrote in a Manhattan Supreme Court affidavit. "Shkreli has harassed me and my family for nearly a year, and his harassment intensified on and around this past Christmas." "Indeed, Shkreli sent multiple unwelcome texts and social media messages to my family and me on Christmas Day."

Pierotti said that Shkreli sent Facebook friend requests to his father and brother in March 2013. On the same day, Pierotti wrote, Shkreli allegedly sent Pierotti's wife a Facebook message saying: "Hi Kristen, I hope you're well. Today we are filing a summons demanding $3 million in damages and penalties from you and your family, specifically your husband ... I'm going to be sending copies of the summons with notice to everyone you and your husband know." Shkreli also allegedly sent Pierotti's wife an October 2013, message on Facebook, saying, "How do you sleep at night? Your husband stole millions from me," according to the affidavit.

Around Dec. 20, 2013, Pierotti said in an affidavit, Shkreli sent a Facebook friend request to Pierotti's 16-year-old son, and then later sent a message saying, "Hey, I'm a friend of your father." "When my son asked why Shkreli sent him a Facebook friend request, Shkreli responded, 'Because I want you to know about your dad ... he betrayed me. he stole $3 million from me,'" Pierotti wrote in his affidavit. Shkreli, on or around Christmas Day that same year, "also sent a Facebook friend request to my 14-year-old son, who never responded," Pierotti wrote. Then, on Christmas Day, "Shkreli sent me a message via LinkedIn, stating simply, 'Scumbag. - Martin Shkreli,'" Pierotti wrote. Pierotti also said in his affidavit that in the next several days, he became aware of the fact that a copy of Retrophin's lawsuit against him had been posted, by someone else, on his own Facebook page, and that his Facebook password had been changed, without his knowledge. He soon afterward discovered that the passwords to his AOL email account, as well as his LinkedIn and Gmail accounts, had also been changed. And on Dec. 26, 2013, Shkreli allegedly sent Pierotti's wife a text message that read, "Hey sweetheart," according to documents attached to Pierotti's affidavit.