Hill doubts Senate staffers 'are qualified to carry out this investigation in a neutral fashion.'
Dr. Grant William Robicheaux and Cerissa Laura Riley are accused of accused of drugging and sexually assaulting at least two women.
The Horry County sheriff said the deputies tried "for a long period of time" to free the patients, but were unable to pull open a back door to the van.
Khalid Masood was in debt, unemployed and estranged from his wife, witnesses say.
Police said that the gunman at WTS Paradigm, a software company, was heavily armed and that officers prevented significant further bloodshed.