。
The suspect hadn't committed that crime.
Literal
Suspect [topic-は] that crime [object-を] commit-was-not-doing.
犯す ('to commit [a crime]') is the standard verb for committing offenses. 犯していなかった is the past ~ていた in negative — 'had not been committing / was not in the state of having committed.' Describes a past state of innocence.