LAX84LA098

During arrival in IFR conditions, the plt was vectored for an ILS rwy 25 apch. At about 0909 PST, he was cleared for the apch & instructed to maintain 3000 ft until intercepting the localizer. A short time later, the controller instructed the plt to contact the tower. At about that time, the controller noted that the acft's transponder reply was indicating about 1700 ft, aprx 1100 ft below the min altitude at that position. The controller immediately queried the plt concerning his altitude, but received no response. According to the plt, everything appeared normal until the acft collided with power lines & crashed. He stated that he believed he had been cleared to 2000 ft, then after intercepting the localizer, he 'began to descend to the glide slope.' An investigation revealed the acft had collided with power lines at an elevation of about 1525 ft. the accident occurred near the outer marker. The min altitude at the outer marker was 2409 ft. no preimpact, sys malfunction or failure was found.