Back in September, there was an unknown arsonist on the loose in Alameda. This arsonist was believed to have been responsible for at least 7 different fires in the city. Soon, however, there were 2 men arrested in conjunction with the crime, one a 27-year-old front man for a local folk band and the other a 22-year-old homeless man. What happened next will surprise you: although the arsons were originally the focus of the police investigation into these 2 men, a search of their homes and further scrutiny of their movements in and around the time the various fires were set has yielded something else, they both now stand accused of other crimes!
It happens more often than you might think. Local law enforcement officials make an arrest and new evidence shows up during the course of the investigation that links an individual to another crime. In this case, the folk singer, and part-time sound engineer, was found to have child pornography on his computer. Meanwhile, it turns out that the transient has been accused of raping an intoxicated woman in a local park.
What this cautionary tale should remind us of is the nature and scope of search warrants. Taking for example the case of the folk singer and formerly accused arsonist, police were allowed to search his home, business, car, or anywhere else they could think of that might lead to evidence against him. This included his computer, where they found the images of child pornography. The thing about search warrants, in other words, is that they allow police officers or other agents of the law to search for any illegal activity, not simply evidence of a particular crime.
You do have at least one option, however, you may ask your legal representative to file a motion that states that the search was unreasonable, that there was not enough information concerning your case to amount to probable cause for the search warrant to have been issued in the first place (CA Penal Code 1538.5). If it can be proven, for example, that the search warrant served on the folk singer was based on flimsy probable cause, then it is possible that the evidence of child pornography discovered during the course of that search will be inadmissible.