Apple, 35, began by apologising to her jailer for being "attitude-y," and continued with a cryptic rant about four other individuals at the jail and "encoding" things she had heard there.
"First thing is, the guy who runs the jail ... he's a good guy, and I want to apologise to him ... for being attitude-y and saying that I didn't trust him, because I didn't, but by the end of the day, I did," Apple told her audience at the Houston concert. Her comments were recorded on video.
The "Criminal" songstress said that "most people were very nice to me," but she had some stern words for a few who she said were less kind.
"There are four of you out there, and I want you to know that I heard everything you did, I wrote it all down with your names and everything you did and said stupidly thinking that I couldn't hear or see you," she continued.
Apple did not name either the jailer or the four individuals, but threatened to make the latter group "famous anytime you ask."
She described the antics of the four people she alluded to as "inappropriate and probably illegal," but did not offer further details.
Apple then announced that she had ripped up the piece of paper, but not before she "encoded" the information she had written down. She said she would "hold that secret forever ... unless you're interested in being a celebrity."
The concert was Apple's first public appearance since she was released from a Hudspeth County, Texas, jail after posting bail on Thursday. The singer was arrested on a felony drug possession charge late Wednesday night when officials at a border patrol checkpoint found four grams of hashish in her possession after stopping her tour bus.
Rusty Fleming, a spokesman for the sheriff in Hudspeth County, said there were seven other people on the bus, but Apple admitted the drugs were hers and everybody else was allowed to drive on.
He said her brief stay in jail passed "without incident."
Apple's representative did not immediately respond to a request for comment.
The singer won a Grammy for the single "Criminal" off her 1996 debut album "Tidal."
