SIOUX FALLS, S.D. (KELO) — A cell phone appears to have revealed details of what happened to Pasqalina Badi of Sioux Falls. The 20-year-old woman was found dead on Monday in a ditch on 275th Street, about a 1/2 mile east of 472nd Avenue, Sioux Falls Police said.
Amir Beaudion, Jr., 19, of Sioux Falls, has been named as a suspect in connection with the alleged abduction of Badi from the Wal Mart at 3020 E. 10th St. early Sunday morning. Beaudion has been in court on charges for another incident.
An affidavit in support of an arrest warrant for Beaudion said Sioux Falls Police requested information for Baldi’s cell phone number.
AT & T provided cell tower data to police for Sunday, Jan. 5. The detective then used a software called CASTViz to better pinpoint the location of activity on Baldi’s cell phone.
Kyle Cronin, an assistant professor of information assurance at Dakota State University in Madison, a cell phone can be used to trace location through triangulation.
CASTViz automatically processes and maps call detail records. It’s a tool developed by National Geospatial Agency (NGA) and the FBI CAST Unit for law enforcement use.
Cronin didn’t comment specifically on the Sioux Falls case or CASTViz but said CASTViz “allows law enforcement to do (triangulation) without calculus.”
Triangulation uses signals carried between a cell phone and a cell tower in order to try and pinpoint a location, Cronin said.
Just as cell phones use signals from cell towers, the cell towers get signals from the cell phone, he said.
“If I can hear signals from three different cell phone towers, I can measure the signal’s strength,” Cronin said.
While triangulation can be done in more remote areas with one cell phone tower, it’s not ideal because the area will be too broad, Cronin said.
An area with multiple towers, such as Sioux Falls, can work well, Cronin said.
The Federal Communications Commission website said Sioux Falls has seven registered cell phone towers but not all towers need to be registered with the FCC.
A circle is drawn around a cell phone tower to indicate the strength of a signal from the tower to indicate a possible location.
Circles are also drawn for a second tower and a third tower, Cronin said.
“All three signals will intersect at one point,” Cronin said.
The intersection will be the point where the signal is strongest from each of the three cell phone towers, he said.
Cronin said when a rock is tossed in a still pond the created wave will reach different areas. “I detect the wave now, you will detect the wave later,” Cronin said.
Again, at some time, there will be a common point where the wave is strongest, Cronin said.
Police learned through CASTViz that Baldi’s cell phone was stationary from 5:14 a.m. to 6:14 a.m. Sunday of 1,000 to 1,500 meters within an area of Interstate 229 and 10th Street. Beaudion Jr.’s address is within that area, the affidavit said.
Police also traced Baldi’s cell phone to an area south of Sioux Falls where it stopped from about 6:41 a.m. to 6:53 a.m. Sunday. The area to where the cell phone was tracked is within the area where Baldi’s body was discovered, the affidavit said The body was found in a ditch on 275th Street, about 1/2 miles east of 472 Avenue.
After 6:53 a.m., cell phone then traveled to an area of Interstate 29 and West 41st Street, the affidavit said. Sioux Falls Police were searching that area on Jan. 8 and appeared to have collected some evidence there.