HALFWAY THROUGH THE ride to Boston, Decker said, “I spoke to my old partner last night.” A beat. “Not my old partner, my former partner. She’s younger than me.”

“Isn’t everyone?” McAdams snapped.

Decker raised his eyebrows but said nothing. It appeared that he had hit a jealous nerve in the kid. It was always surprising what set people off.

The kid fidgeted. “Why’d you call her? Never mind. It’s none of my business. Unless you were talking about the case. Then it is my business. Aren’t you the one who told me to keep my mouth shut?”

Decker ignored his ’tude. “Her department isn’t nearly as big as LAPD, but it’s in a major city and she has access to a lot more databases than we do. I’ve asked her to look into any art crime that might have involved homicide within the last five years. It’d be interesting to see if she comes up with anything new.”

McAdams was silent. He sipped coffee from a thermos.

“Anything left in that thing?” Decker asked.

“Dregs.”

They drove for five minutes without speaking. Then Decker spotted a Dunkin’ Donuts. “Let’s get a refill.”

“Doughnuts and coffee. Very cop of you.”

“You want something to eat? I’m going to get a bagel.” When McAdams remained silent, Decker said, “I’ll take that as a no.” It took him five minutes to make the round-trip. When he came back, he unwrapped his bagel and took a bite. “Sure you don’t want anything?”

“I’m fine, okay?”

“Sure.” Decker continued eating.

McAdams blew out air. Then he got out of the car and came back a minute later with his own bagel and a cup of coffee. “Did she have anything illuminating to add to the case?”

“She’s smart enough not to offer opinions without having the facts in front of her. Mostly she just listened to my frustration. She agrees with us, that it has to be something more than just a couple of Tiffany panels.”

“Insightful, that woman is. What’s her name again? Maude?”

“Marge Dunn. She and her fiancé may come out in the summer to visit.”

“How old is she?”

“Marge is a little older than Rina’s age . . . early fifties. We both left LAPD at the same time. I don’t miss the department, but I do miss her. You’re with someone that long, it’s like a marriage.”

“Was she your little piece of action on the side?”

Slowly, Decker smiled. “No, she was not my little piece of action on the side. I don’t have action on the side. I’m a true blue guy. But I thank you for the compliment: that I could get action on the side . . . had I wanted it.”

McAdams just shook his head. “You are absolutely unflappable.”