My boss has asked me make a device which is capable of scanning rooms for bugs!
Consider a new job. :)

Apart from that, you could try and rent a spectrum analyzer from an equipment rental service, build a simple loop antenna (cut the end off a coax cable, loop some wire from the center conductor to the ground braid) and 'sniff' around the room to see if there's any spurious RF transmissions coincident with the "tii-ee, tii, teee ti ti" noises.