At one point during the interrogation, the investigators even threatened to have his pet Labrador Retriever, Margosha, euthanized as a stray, and brought the dog into the room so he could say goodbye. “OK? Your dog’s now gone, forget about it,” said an investigator.
Finally, after curling up with the dog on the floor, Perez broke down and confessed. He said he had stabbed his father multiple times with a pair of scissors during an altercation in which his father hit Perez over the head with a beer bottle.
Perez’s father wasn’t dead — or even missing. Thomas Sr. was at Los Angeles International Airport waiting for a flight to see his daughter in Northern California. But police didn’t immediately tell Perez.
According to cases settled by the supreme court, you have to be clear, unambiguous, and express you’re invoking your right in a way that “the average police officer can understand the person’s intent to actually invoke their rights”.
In practice, this means no slang, no “maybe” or “possibly”. It’s best to be direct and simple. Something like “I am invoking my right to remain silent and I am invoking my right to an attorney”. IANAL and have not been arrested though, but this is advice I’ve been given from cops in the family and seen reiterated before.