How San Bernardino Shooters Were Hiding in Plain Sight

Neighbors and colleagues had few suspicions.

— -- The home of the suspected mass shooters believed to be responsible for the San Bernardino, California, shooting this week looks like that of any family with a newborn.

The couple left their 6-month-old daughter with one of their mothers before allegedly going on the shooting rampage. The infant is no longer at the family's Redlands, California, home, but many of her toys remain behind.

A copy of a book with goodnight stories inspired by the Quran was also spotted inside the little girl's room.

Everything appeared so normal that neighbors and colleagues of Farook, 28, and Malik, 29, say they had no idea the people living and working next to them were planning a deadly attack.

Farook's San Bernardino colleague and cubicle-mate, Patrick Baccari, said he had tried to connect with Farook but had little success.

"I thought I made a connection with him, talking about preparing cars and things like that. Asking some of his experiences, things like that," Baccari told ABC News.

"Usually, I'd grate him and I wouldn't get anything back. It's like you're trying to initiate some conversation and it just doesn't perpetuate or get anywhere.”

One person who noted an uptick of activity at the couple's home the week before the attack was their loal UPS driver, who noted that Farook was unfriendly during one recent interaction.

The delivery man who worked the area, but asked not to be named, confirmed to ABC News he had delivered packages to the Redlands home as recently as late last week, just days before the Wednesday attack.

Some days, the UPS driver noted, he would deliver over a dozen a day.

On one particular day last week, the driver said, Farook had to help him carry the packages in because there were so many. The driver said they were mostly light, bagged packages and many of them were from Target.

When the driver asked whether they were Christmas gifts, Farook glowered at the driver, he said.

Get real-time updates as this story unfolds. To start, just "star" this story in ABC News' phone app. Download ABC News for iPhone here or ABC News for Android here.