This is in Washington State

I am unfamiliar with how the Defense attorney receives evidence from the prosecution. I thought they had to do this within a certain time frame. Here is my example:

The case started over 9 months ago. I had a police report that was filed 3 1/2 months before trial WAS scheduled. A summary of facts was sent to the prosecutor 2 months after that. Then two weeks before trial, or a month after the summary of facts, my attorney discovered this piece of evidence on his own during an interview with the accuser. Wasn't my attorney supposed to be given these reports and any evidence? Can the prosecutor sit on new evidence for a month? Actually the prosecution didn't volunteer this information. We had to ask that it be given to us after we found out about it.

This caused a serious delay in the trial. I feel like my rights to a speedy trial have been violated over and over by the prosecutor witholding evidence. We had to go for a continuance because of this. It really pisses me off because if the report had been sent in a timely manner we would have been ready for trial. They continually do this as well. I have found other evidence on my own that they have that has been witheld. I am not sure if my attorney even knows yet. It is rediculous.

How long can a prosecutor withold evidence from the defense?