One of the most common defenses to marijuana possession charges concerns illegal search and seizure by law enforcement officers. When police seize marijuana in particular circumstances without a warrant or probable cause, it may be possible that the evidence will be inadmissible and the criminal charges thrown out. In many constructive possession cases, an alleged offender could argue the marijuana belonged to another person. Some people in Texas may have medical marijuana that was legally purchased in another state, and the suspected marijuana in some cases may not have been cannabis. It is also possible for a minimal number of instances to involve entrapment or planted drugs.