"I killed Jennifer," he allegedly told a woman whom his sister had summoned for help.
The horrific crime unfolded while Ebichi's two children were in the house, investigators say. It shook the quiet subdivision that was home to the growing family, where Christmas lights shined as police processed the scene on Friday night.
"This was a shock for us," neighbor Ben Nguyen told the Austin American-Statesman from his front porch. "It's not something we expected to happen here. They were good people."
Michael Egwuagu, 25, was arrested on a murder charge - a stunning turn for the once widely admired University of Texas-San Antonio defensive captain, who went by the nickname "Egg."
Part of a family of football players, with former Buffalo Bill Ikemefuna "IK" Enemkpali as a cousin, he was closely watched since his days at Pflugerville's John B. Connally High School. He dreamed of playing for the NFL, telling reporters in 2017, a year after graduating college, that being drafted "would mean the world to me and my family."
He signed with the Chicago Bears that spring as an undrafted free agent, but was cut shortly before the start of the season.
More recently, Michael Egwuagu was focused on trading stocks and pursuing another old dream of becoming a rapper, according to a November 2018 story on Rivals.com, which described him as a "renaissance man."
It's not clear what led to Friday's attack. A spokeswoman for the sheriff's office, Kristen Dark, said she could not respond to inquiries into whether the former football player had a history of mental illness.
According to the arrest report, authorities got a 911 call summoning them to the house just before 5pm on Friday. Deputies found Ebichi, who was in her first trimester, with more than a dozen stab wounds. Her alleged attacker was nude in the street. On the ground near him was a bloody knife.
The woman Ebichi had asked for help told investigators that when she got to the house, she heard the mother and her children screaming and Michael Egwuagu yelling inside. She said he walked out smiling and holding a knife. That was when he confessed to killing his sister, the report says.
"Michael then walked out into the street and got onto his knees as though he was praying," it continues.
Martin Egwuagu arrived soon after. He told police he saw one of Ebichi's children covered with blood in the front yard, accompanied by the woman Ebichi had asked for help. The other child was in the house with her mother, crying. Martin Egwuagu gathered the children and then encountered his brother, who told him he was "one of the good ones," according to the report.
Police took Michael Egwuagu into custody that night. Sheriff's office records show he is being held at the Travis County Correctional Complex on $500,000 bond. His attorney, Krista Chacona, could not be reached for comment on Tuesday.