Five Arrested in Shooting Investigation 
On August 9, 2026, at approximately 12:31 a.m., the Rock County Communications Center received numerous 911 calls reporting a disturbance in the 100 block of South Academy Street in the City of Janesville. Callers reported numerous people yelling and a physical altercation occurring. Prior to officers arriving, the altercation escalated, and multiple shots were fired. Witnesses reported hearing approximately two to six gunshots and later reported seeing a gray sport utility vehicle leaving the area.
Upon arrival, officers located three individuals who had sustained gunshot wounds. One individual also sustained an injury to the face after being struck in the head by a firearm. Officers provided immediate medical assistance until Janesville Fire Department personnel arrived. Despite lifesaving efforts, one of the three shooting victims died as a result of his injuries. The decedent was identified as Jason Kaplan, age 25.
During the investigation, officers from the Beloit Police Department located the gray sport utility vehicle believed to be associated with the incident in the City of Beloit. Beloit officers subsequently took the driver, Mantezz Granger, into custody. Granger was arrested on charges of Party to a Crime—First-Degree Intentional Homicide, three counts of Party to a Crime- Attempted First-Degree Intentional Homicide, and two counts Party to a Crime—Recklessly Endangering Safety. Mantezz was later transported to the Rock County Sheriff’s Office, where he will await his initial court appearance.
At approximately 1:30 p.m. on August 9, 2026, the Janesville Police Department SWAT Team served a search warrant in the 1800 block of South Crosby Avenue. Evidentiary items seized that were not related to the shooting investigation included drug paraphernalia and U.S. currency. Charles Crenshaw later turned himself in at the Janesville Police Department. Crenshaw’s involvement is still being investigated. He was later arrested for a Felony Probation Violation and transported to the Rock County Sheriff’s Office.
The Janesville Police Department requested mutual aid from the Rock County Sheriff’s Office. At approximately 6:00 p.m., the Rock County Sheriff’s Office SWAT Team served an additional search warrant in the 700 block of East Philhower Road in the Town of Beloit as part of the ongoing shooting investigation after Town of Beloit officers observed suspect Demetrius Cooper leaving the residence.
Demetrius was taken into custody and arrested on charges of Party to a Crime—First-Degree Intentional Homicide, three counts of Party to a Crime—Attempted First-Degree Intentional Homicide, and two counts of Party to a Crime—First-Degree Reckless Endangering Safety. Demetrius was later transported to the Rock County Sheriff’s Office, where he will await his initial court appearance. Evidentiary items were seized from the residence.
On August 10, 2026, at approximately 4:00 p.m., Tyshawn Howe turned himself in at the Janesville Police Department lobby. Howe was taken into custody and arrested on charges of Party to a Crime—First-Degree Intentional Homicide, three counts of Party to a Crime—Attempted First-Degree Intentional Homicide, and two counts of Recklessly Endangering Safety. Tyshawn was later transported to the Rock County Sheriff’s Office, where he will await his initial court appearance.
The Janesville Police Department requested mutual aid from the Green County Sheriff’s Office. On August 10, 2026, at approximately 9:00 p.m., the Green County Sheriff’s Office multi-jurisdictional SWAT Team, with assistance from the Rock County Sheriff’s Office and the Janesville Police Department, served a search warrant. Marshaun Jones was taken into custody and arrested on charges of First-Degree Intentional Homicide, three counts of Party to a Crime—Attempted First-Degree Intentional Homicide, and two counts of Party to a Crime—First-Degree Reckless Endangering Safety. Marshaun was later transported to the Rock County Sheriff’s Office, where he will await his initial court appearance. Evidentiary items seized included ammunition, clothing, and cellular phones.
The Janesville Police Department also requested mutual aid from the Madison Police Department. On August 10, 2026, at approximately 11:50 p.m., the Madison Police Department conducted a consent search in the 00 block of Kessel Court with an adult homeowner who has previous ties to Janesville.
The Janesville Police Department would like to thank the numerous law enforcement agencies that assisted and continue to assist throughout this investigation. The willingness of our law enforcement partners to share information, resources, and investigative assistance was instrumental in allowing investigators to quickly follow leads and identify individuals believed to be involved in this incident.
At this time, there is no evidence of an ongoing or direct threat to the community related to this incident. Information obtained from witness statements, video surveillance, and evidentiary items suggests that multiple people were armed with firearms during the physical disturbance and more than one person discharged a firearm. All suspects involved in the physical altercation have been arrested.
The Janesville Police Department’s Patrol Division, Street Crimes Unit, and Detective Bureau are continuing to work together to investigate this incident. Due to the ongoing nature of this investigation, no additional information will be released at this time. Information will be released when it can be provided without compromising the investigation.
Anyone with information regarding this incident is encouraged to contact the Janesville Police Department at 608-755-3100, the Rock County Communications Center at 608-757-2244, or Crime Stoppers at 608-756-3636. Tips may also be submitted anonymously through the P3 Tips smartphone application.
Arrested:
Mantezz Granger
20 years of age
Party to a Crime-First Degree Intentional Homicide
Three counts Party to a Crime- Attempted First-Degree Intentional Homicide
Two counts Party to a Crime—First Degree Recklessly Endangering Safety
Charles Crenshaw III
20 years of age
Felony Probation Violation
Demetrius Cooper
19 years of age
Party to a Crime—First-Degree Intentional Homicide
Three counts of Party to a Crime—Attempted First-Degree Intentional Homicide
Two counts of Party to a Crime—First-Degree Recklessly Endangering Safety
Tyshawn Howe
19 years of age
Party to a Crime—First-Degree Intentional Homicide
Three counts of Party to a Crime—Attempted First-Degree Intentional Homicide
Two counts of First Degree Recklessly Endangering Safety
Marshaun Jones
21 years of age
First-Degree Intentional Homicide
Three counts of Party to a Crime—Attempted First-Degree Intentional Homicide
Two counts of Party to a Crime—First-Degree Reckless Endangering Safety
| Incident Number: JV2636472 |
| Location: 100 Block of South Academy St |
| By: Lt. Jennifer Seeger |
| Date: 08-11-26 |
| Pursuant to the directive of the Wisconsin Supreme Court, as found in Supreme Court Rule 20:3:6 Trial Publicity, you are advised that a charge is merely an accusation and that a defendant is presumed innocent until and unless proven guilty. |
Address/Location
Janesville Police Department
100 N Jackson St
Janesville, WI 53548
Contact
Emergency: 9-1-1
Non-emergencies: 608-755-3100
