Unfortunately, you don't say what you found in the wreckage. Most people don't actually do much of an autopsy after a crash, especially if they think they know the answer and it doesn't include a failure in the aircraft. Which is what it sounds like here.

If the elevator pushrod had failed, the connector come loose at the elevator horn, connector come loose at the servo, arm come off the servo, extension come loose from radio, come loose from servo plug, any wires failed internally (broken in previous crashes or whatever) switch failed, battery connection to switch, etc

A good autopsy often finds the cause when it's in the airplane. And it very often is.