The chairman of the Senate Judiciary Committee is asking the U.S. Justice Department for information about how aggressively it pursues elder abuse in nursing homes, particularly cases in which workers share degrading photos or videos of residents on social media.

Sen. Charles Grassley, R-Iowa, sent a letter Monday to Attorney General Loretta Lynch following a ProPublica article in December that identified some three dozen instances since 2012 in which workers at nursing homes and assisted-living centers have surreptitiously shared photos or videos of residents, some of whom were partially or completely naked. At least 16 cases involved Snapchat, a social media service in which photos appear for a few seconds and then disappear with no lasting record.

Since the article was published, there have been at least two additional incidents. (Read details of each case here.)

Grassley is the third senator to call for action following ProPublica’s report. In December, Sen. Joe Donnelly, D-Ind., requested an investigation by the Senate Aging Committee. And last week, Sen. Tom Carper, D-Del., asked federal privacy regulators what, if anything, they are doing to stop the inappropriate behavior.

“As technology and social media expand, we owe it to our nation’s elderly population to ensure quality nursing home care, which debasement of patients does not fulfill,” Grassley wrote.

Inappropriate Social Media Posts by Nursing Home Workers, Detailed See details of the incidents since 2012 in which workers at nursing homes and assisted-living centers shared photos or videos of residents on social media networks. Read more.

He asked the Justice Department what steps it is taking to combat elder abuse by means of social media and to quantify the number of civil and criminal cases the agency has handled in this area in the last five years. Criminal charges have been brought in many of the incidents ProPublica identified, but they typically are handled by state or local prosecutors, not the federal government.

“The posts are degrading and horrifying,” Grassley said in a statement. “The residents are frail and incapable of fighting back against the abusive treatment.”

The Justice Department has received Grassley’s letter and is reviewing it, a spokesman said.

Greg Crist, a spokesman for the American Health Care Association, the nursing home industry trade group, said his group takes the matter seriously and has been holding training sessions around the country on social media use in nursing homes. Inappropriate postings, he said, are “infrequent and uncommon.”

"While rare, posting these sorts of pictures is wrong,” he said in an email. “Our association has been actively working in recent months not only to stress the clear violations of an individual’s privacy, but more broadly, to educate staff and personnel on the boundaries needed when active across all social media platforms.”