K2961 Mosfet Equivalent
It's in a rarely found Japanese extended TO-92-style through-hole package (probably an internal leadframe tab for higher power dissipation) and has relatively low input capacitance and relatively high Id/Idp. 

Frankly, I think you'd be better searching for the exact part if you're not able to reverse engineer the circuit.

Look for a 2SK2961. The 2S is a Japanese thing - they leave it off. You can find replacement parts for a dollar or two.