A Palestinian security agency has launched an internal investigation into an assault against a human rights activist by one of its officers, officials said Monday. Preventive Security commander Ziad Hab al-Rieh issued the directive in response to a complaint by the PA's official rights ombudsman, Palestinian security officials told Ma'an. The officer is accused of assaulting Yazan Sawafta, an attorney and legal researcher for the Independent Commission for Human Rights, during a protest by relatives of prisoners held by the Palestinian Authority. Members of the independent commission spoke out angrily after the Jan. 9 attack on Sawafta, who was documenting the sit-in and answering reporters' questions about politically motivated arrests. "I was repeatedly beaten on my chest and legs and threatened (with indictment)," Sawafta said in an affidavit, adding that his camera, identity card and official papers were seized by the officer. "They did not stop ... until other members of the service intervened. This act was inhuman and degrading treatment especially as it took place in public and in front of other members of the security services." The findings of the investigation could result at most in disciplinary rather than judicial action, a disappointing outcome for activists who hoped the PA would take a stronger line. "A possible disciplinary penalty instead of a criminal inquiry seems grossly inadequate for the brutal, public beating of a human rights defender," said Bill van Esveld, a Jerusalem-based researcher for Human Rights Watch in Israel and the occupied Palestinian territories. "This is a missed opportunity to end the terrible record of impunity for abuses by the PA's security services." Human Rights Watch and other groups say there has never been a case in which a Palestinian Authority security officer was convicted of abusing people despite numerous credible allegations. Preventive Security officials maintain they are committed to freedom of speech and human rights, noting that an investigator was dispatched to meet with the commission soon after the incident on Jan. 9. The agency also formed two investigation committees -- the internal one as well as a joint panel with the commission, and it has met with the rights body's board of directors and other officials. Discussions over the past week with the joint investigative committee have been positive so far, said Ahmad Harb, the independent commission's head of the board. "They are taking the matter seriously," he said. "Let us see the results of the investigation, what they are going to do, and if they do something satisfactory. I hope they will." 'Not an isolated incident' Harb emphasized he was primarily concerned with the behavior of the individual officer, rather than the agency. The circumstances demand more than "just investigating," Harb said. Al-Rieh, the commander, should take action against the accused officer who is "well known for causing problems," he added. While the commission is not pursuing criminal charges, it has lodged a complaint with the UN special rapporteur on the situation of human rights defenders, according to documents seen by Ma'an. The complaint, signed by executive director Randa Siniora and dated Jan. 12, calls on Margrette Sekaggya to intervene with the PA and report back on any response from the government. The independent commission "considers any attack on citizens by government officials is a crime punishable by law, and violation to the human rights and dignity of all persons," the complaint says. PA officials "know they should take measures" against the officer, Siniora said. The officer has a history of obstructing the rights body's work, the complaint notes. Two years earlier, he forced himself into its headquarters and threatened a member of staff, it says. The memo recalls the same officer angrily quizzing commission members about a 2009 news release which alleged his unit had used excessive force against a lawmaker aligned with Hamas. According to the commission's records, the officer "threatened that he will return" to the office building and "take action" against the staff member who documented the incident.