The title is blunt on purpose. Brian Foley prosecuted felonies in Harris County for years, and the pattern was consistent enough to state as a rule. He explains in this video.
What prosecutors actually rely on
Physical evidence is rarer than television suggests. Most cases are built on witness accounts, officer observations, and — above all — the defendant's own statement. A statement supplies the elements the State otherwise has to infer: knowledge, intent, presence, possession. It also gives the prosecutor something to hold up in closing argument: "In his own words."
The cases that get dismissed
When the defendant said nothing, the State is left with what it can prove independently. In a drug case, that may be a bag in a car with three people in it. In an assault case, a complainant whose story has changed twice. In a theft case, grainy video of someone who might be the defendant. Those cases get dismissed, reduced, or won at trial — because there is no statement to fill the gaps.
How to invoke the right
The right to remain silent has to be invoked; simply staying quiet can be used against you in some circumstances, and answering "just a few" questions waives it for those questions. Say it plainly: "I am invoking my right to remain silent, and I want a lawyer." After that, say nothing else — to the officer, to the detective who "just wants your side," or on the jail phone.
Brian Foley and Luis Baez know which cases could not have been prosecuted without a statement because they prosecuted them. Call or text (713) 703-1718 — before you talk to anyone else.