Green’s Dictionary of Slang

1. to suspect; thus sussed, suspected.

1953		D. Webb Crime is my Business 202: He turned to Hodge and said, ‘Who’s sussed for this job?’ .
1962		F. Norman Guntz 154: I sused that they must have been some of his ancestors.
1985		B. Humphries Traveller’s Tool 35: They can sus you’re guilty.
2001		N. Griffiths Sheepshagger 95: If I had’ve fuckin shared a house with the bastard then I would’ve fuckin sussed that something was up.

2. see suss out v.