Owain Yeoman is in fact Welsh; he puts on the American accent he uses, which even fooled the other cast members, as he always stayed in character, even when the cameras weren't rolling.
In most of season five, Amanda Righetti (Grace Van Pelt) was pregnant. Since it didn't fit in with the story line, she can only be seen sitting behind a computer or in dark shadows in almost every scene, and doesn't go into the field.
Lapsang souchong, the tea that Patrick Jane drinks, is a type of black tea originating from China. Black tea is called "hong cha" in Chinese, which translates literally to "red tea".
In most episodes the victim or perpetrator has a name indicative of his true character. Examples: McTyranny, Quick, Just, Unjust.
The show has included several real life family members of the cast: Owain Yeoman's (Wayne Rigsby) then wife, Lucy Davis, appeared in the episode 18-5-4 (2010) as Daphne Valiquette, while Simon Baker (Patrick Jane)'s wife, Rebecca Rigg, daughter, Stella Baker and son, Claude, have all made appearances. Rebecca appeared in A Dozen Red Roses (2009) as Felicia Scott; Claude appeared in Red Sails in the Sunset (2012) and Stella appeared in The Greybar Hotel (2014), as the Angry Inmate.