In the plus column, the Harringtons received a check every month from the state for Ozzie; also, Denise had just gotten a modest raise at her receptionist job. Judging by the going rate in Dorchester, the family could hang on if they got the upper two floors rented. Phil and Professor Alex were going to walk through the space this evening to estimate just how close Patrick might have been to that goal.

And if the Harringtons did lose the house? Patrick’s first wife was dead; Denise’s first husband, out of the picture. Did Patrick or Denise have other family that could take them in? Was there a possibility of them receiving assistance from the church?

D.D. wanted answers to those questions. Better yet, she wanted to find out if Denise or Patrick had made the same inquiries. From their perspective, how deep was the chasm that loomed in front of them? Was it a matter of Oh well, we can always move in with brother Joe? Or was it Dammit, we’re facing three kids in a homeless shelter with no hope of getting out?

Eighteen hours after the initial call, D.D. had four dead, and one in critical condition. For suspects she got to choose between a middle-aged family man and his nine-year-old psychotic son. The father had more physical capability. The son had more mental inclination.

Which brought her and her new shadow, Professor Alex, to the Pediatric Evaluation Clinic of Boston, part of the Kirkland Medical Center.

First steps into the locked-down psych unit weren’t what D.D. expected. The ceiling yawned nine feet above. Natural light poured in massive windows to illuminate pale green carpeting and soft blue walls. Built-in benches featured fabrics dotted with small yellow ducks, while a cluster of wooden tables bore buckets of Legos. Place reminded her of a waiting room in an upscale pediatrician’s office. Except the kids checked in for a much longer stay.

D.D. was just turning toward Alex when a black girl with twin braids flapping underneath her red helmet whizzed by on Rollerblades. A second later, a smaller boy in sagging blue sweatpants followed in hot pursuit, not as well balanced, but churning forward for all he was worth.

D.D. jumped back. Alex, too.

“Becca, Arnie, not beyond the orange cone!” a man’s voice boomed. The girl and boy each turned—her gracefully, him awkwardly—then raced back the other direction, barely missing D.D. and Alex a second time.

“Sorry,” the man called out, sounding more amused than annoyed. A younger guy with buzz-cut brown hair, he stood next to an orange cone in the middle of the hall. He looked like a gym coach, wearing blue sweatpants and a white T-shirt that defined a well-developed set of pecs. In his hand, he carried a clipboard, while a lanyard bearing ID and a set of keys jangled around his neck.