(CNN) -- When Longmont, Colorado, police officers Billy Sawyer and Phil Piotrowski responded to a 911 call from a pregnant woman who was stabbed and had her fetus ripped out, they weren't prepared for what they would see.
"She was covered from head to toe in blood," Sawyer told CNN affiliate KDVR. "So I put some gloves on and held her hand and went through where her injuries were ... trying to figure out exactly what we had."
Michelle Wilkins was weak and in shock when the officers arrived.
"I started yelling and Michelle yelled back, very faintly, and it was muffled -- 'Help me! Help me!'" Sawyer said.
The grisly cutting of the fetus from Wilkins began when she responded to a Craigslist ad about baby clothes for sale.
The 26-year old Wilkins, who was seven months' pregnant, arrived at the seller's home Wednesday in Longmont. Stabbed in the stomach and bleeding, Wilkins called 911.
The scene was almost too much for Piotrowski to bear. He had to take a moment to collect himself.
"When I walked in and looked at her for a short moment, I actually had to walk out for a second because my head wasn't able to wrap around it."
Still, given what the 26-year-old woman had endured, it left him impressed.
"She is probably one of the strongest people I've ever had the pleasure to meet," Piotrowski said.
Michelle Wilkins' uncle Chris Wilkins said, "She's alive because professional first responders execute perfectly." But Piotrowski believes Wilkins is the one who "saved her own life."
The fetus died, but the mother survived and "is improving minute by minute, hour by hour," according to Chris Wilkins. She's reported to be in critical but stable condition.
Dynel Lane, 34, a former nurse aide, is being held on $2 million bail while prosecutors weigh charges against her, including murder. Lane is accused of stabbing Wilkins and removing a female fetus. The murder charge would reportedly depend on whether the fetus was old enough to have lived outside of her mother's body.
In a statement obtained by KDVR, Michelle Wilkins' family says, "We cannot begin to fathom the depths of depravity and evil which drove her attacker, and trust that between law enforcement and our legal system; they will make sure justice is carried out."
CNN's John Fricke contributed to this report.
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