suspect of
suspect (someone or something) of (something)
To consider or believe that someone or something is guilty of some crime or wrongdoing but lacking evidence to prove it. I began to suspect him of having an affair when he started leaving the house at odd hours and was evasive when I asked him where he was going. The feds suspect the company of fraud, but they have to build a portfolio of evidence before they can strike.
suspect someone of something
to think or believe that someone has done something. I suspect the clerk of stealing. Ted was suspected of leaving the door unlocked when he left last Friday.