‘While You Were Sleeping’: Crime scene investigators tasked with collecting evidence, even in dark

Expert eyes look for clues that play into criminal cases

SAN ANTONIO – Most people know them by three little letters, C. S. I., but what crime scene investigators do has an impact on hundreds of criminal cases in the city of San Antonio each year.

As their name implies, their job involves showing up at crime scenes to collect evidence.

“We can have anything as simple as doing some narcotics tests for officers or it can get as crazy as responding to murders,” said Olinda Cardenas, a CSI for the San Antonio Police Department for the past 10 years.

It’s a job that, in itself, can be taxing.

Cardenas, however, has the added challenge of searching for those clues in the dark.

She is among those who work the overnight shift, known within the police department as “dogwatch.”

“It's not as glamorous as TV. It's hot. The conditions can be a little rough some times. But I have fun doing it,” she said.

Angela Salvatierra also spends her nights on the streets as a crime scene investigator.


She says a longtime interest in law enforcement drew her to the career 20 years ago.

“But I had absolutely no interest in running down bad guys or carrying a firearm,” Salvatierra said.

Instead, she tracks down the traces of what they’ve done.

Many times, she says, it can take a toll and she has to find a way to turn off her emotions.

“If I were to stand there and really think about a scene or think about a body and allow myself, I could cry over it,” Salvatierra said. “I could go home and I could cry at night.”

Ultimately, the evidence these overnight investigators collect does see the light of day, in a courtroom.

It often plays a big role in many of the criminal cases when suspects go to trial.

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