The Lead Interrogator was a high ranking scientist whose task was to interrogate the four remaining survivors of the USG O'Bannon incident. He was also one of the main human villains in Dead Space Aftermath.
He started the interrogation sessions with Nikolas Kuttner and then proceeded to interrogate Alejandro Borges. After that, he continued with Stross and finally, he interrogated Isabel Cho.
As it turns out, his orders were to dispatch any of the survivors who had not come in contact, direct or indirect, with the Marker fragment.
After the interrogation sessions, he was supposedly congratulated by the Overseer only to be killed shortly after in order to keep him quiet.