ST. PAUL — An ex-girlfriend’s allegation that Minnesota Rep. Keith Ellison once physically abused her could not be substantiated because she refused to provide video she said she had of the incident, an attorney with links to the state’s Democratic Party who was hired to investigate the claims concluded in a draft report obtained by The Associated Press.

The party launched an investigation after Karen Monahan alleged in August that the Democratic congressman dragged her off a bed by her feet while screaming obscenities at her in 2016. Ellison, also a deputy chairman of the Democratic National Committee, has denied the accusation.

Monahan said she had video footage of the incident and leveled the allegation just days before a crowded Democratic primary for Minnesota attorney general that Ellison went on to win. But she declined to turn over the video during the investigation conducted by attorney Susan Ellingstad, a partner at the same Minnesota law firm as Charlie Nauen, the top lawyer for Minnesota’s Democratic-Farmer-Labor party.

In her report , Ellingstad noted Monahan’s shifting rationale for refusing to produce the video footage, including that it was lost, on a USB drive in storage or that it was too embarrassing and traumatic to release. Ellingstad also wrote that Monahan would not allow her to view the footage privately, and that Monahan’s sons — who claimed to have seen the video — declined interviews.

“An allegation standing alone is not necessarily sufficient to conclude that conduct occurred, particularly where the accusing party declines to produce supporting evidence that she herself asserts exists,” Ellingstad wrote. “She has thus repeatedly placed the existence of the video front and center to her allegations, but then has refused to disclose it.”

Democratic party chairman Ken Martin confirmed the report’s authenticity Monday. In a statement, he said he would forward it to law enforcement to “determine whether further investigation is warranted.”

The draft report obtained by the AP was not dated, but it notes Ellingstad tried to reach Monahan on Sept. 26 to request a “final opportunity” to view the video. It’s not clear when the party will release the full report.

Neither Monahan nor Ellison’s campaign immediately responded to requests for comment Monday. Andrew Parker, who Monahan retained as legal counsel, said he had not seen the report and declined to comment.

Democrats in Minnesota are concerned the allegations could impact their chances in November to hold on to the attorney general’s office, which the party has held for more than four decades. Public polling shows Ellison in a close race with Republican Doug Wardlow, a little-known former state lawmaker who has said the allegations make Ellison unfit for office.

Wardlow dismissed the report as a “sham,” given Ellingstad’s proximity to the state Democratic party’s attorney. Earlier Monday, Republican U.S. Senate hopeful Karin Housley called for the attorney general’s office to investigate the allegation, saying it could provide “an impartial investigation into the serious allegations.”

The allegation against Ellison has loomed over his bid for attorney general and Democrats nationwide as they push for answers surrounding the sexual assault allegations against Supreme Court nominee Brett Kavanaugh.

Ellison was first elected to his Minneapolis congressional district in 2006 and emerged as a leader among liberal Democrats, including co-chairing the Congressional Progressive Caucus.

Ellison and Monahan dated for several years but broke up before she accused him of physical abuse. Ellingstad’s report paints a picture of a tumultuous relationship marked at times by anger and Monahan’s accusations that Ellison had been unfaithful.

Monahan began suggesting she was the victim of emotional and physical abuse on Twitter in late 2017, but she didn’t identify Ellison until Aug. 11, when Monahan’s son posted about the alleged incident on Facebook. Ellison went on to win the Aug. 14 Democratic primary for attorney general.

According to Ellingstad’s report, Monahan and Ellison agree that their arguments came to a head in August 2016, when Ellison lied to Monahan about meeting with a female friend. Ellison said he then broke up with Monahan because “he knew he could not tell her the truth because she did not trust him, and he did not want to be in a relationship where he had to lie.”

Monahan accused Ellison of flying into a rage. She said he tried to pull her off the bed by her feet the next day, while he screamed obscenities at her, saying she began recording video of the incident as the altercation began. Ellison maintained he had had never emotionally or physically abused Monahan, though he admitted he once called her a derogatory term during an argument in 2013 and left the house without speaking to her.

Monahan eventually moved out of Ellison’s house. Ellison said they talked about getting back together throughout the fall and winter of 2016 but never did so, and that he became romantically involved with other women.

Monahan contends the pair was still together and that she broke up with Ellison in early 2017 after learning Ellison had been involved with other women. She began posting on Twitter about emotional and “narcissistic abuse” soon afterward.