Interesting. “What about cameras?” he asked as he moved through the house, clearing it of potential bad guys. Looking through every room, every closet.

Mackenzie kept close to him. “What about them?”

“If you have security cameras, those could tell us something about what happened to your brother.”

“Good idea. But I don’t think they’ll tell us anything about his death.”

“Because?”

“The cameras would show him collapsing, and that’s all.”

“But how do you know someone wasn’t here with him?” Alex held his weapon ready, flipped on lights, and searched the next room.

“That’s a fair point.” She shivered behind him. “I had planned to get into the security cameras, just so you know.”

He cleared the kitchen. “How hard would it be to hack into a pacemaker?”

“That’s not my expertise, but I have a friend in cybersecurity whose job is to hack into medical devices to test their security, and I can ask her.”

Interesting. Next room—the library. “The fact that there is such a job is worrisome.”

“Exactly.”

He paused at the bottom of the stairs to the second floor.

She stared at her cell and typed. “Sending her a text.” Then she looked at him. “I don’t know when I’ll hear from her. Looking at it from my limited knowledge, the hacker could insert malware into the system and then when the device connects to the internet to send or receive data, the malware is—”

“Downloaded and can cause a malfunction. The same way it happens to any electronic device.”

She nodded. “But it’s really unheard of—at least that we know about. That kind of news getting out would cause panic. Besides, hackers are usually more interested in identity theft.”

“But you think it could happen.”

“Yes. His pacemaker could be associated with an older system that wasn’t updated with patches or a new system with a zero-day vulnerability. If someone wanted to commit a murder that would be hard to discover, this would be it.”

His gut tightened at the idea. “What would a cybercriminal do, exactly?”

“Deplete the battery? Alter pacing? Even if the hacker couldn’t gain access to the hospital intranet system, he could hack in by proximity to the medical device or the home transmitter.”

“You mean kind of like hackers use RFID skimmers to get credit card numbers and personal information by just sitting next to you at the airport.”

“Yes.” She held his gaze and rubbed her arms.

“Meaning, his killer could have been close.” Could still be close.

Her face paled. “Let’s see what the pathologist tells the coroner, assuming the pacemaker is even examined as part of the autopsy. In the meantime, I’ll find out what my friend has to say.” She smiled, then glanced at her cell. “And here’s her answer.”