Wis. Stat. § 968.07
If the police have probable cause for arrest without a warrant, they may break down a door to effect the arrest after announcing their purpose in demanding admission. The remedy for excessive force is not dismissal of the criminal charge. Nadolinski v. State, 46 Wis. 2d 259, 174 N.W.2d 483 (1970). An arrest based solely on evidence discovered after an illegal search is invalid. State ex rel. Furlong v. Waukesha County Court, 47 Wis. 2d 515, 177 N.W.2d 333 (1970). While probable cause for an arrest without a warrant requires that an officer have more than a mere suspicion, the officer does not need the same quantum of evidence necessary for conviction, but information that would lead a reasonable officer to believe that guilt is more than a possibility, which information can be based in part on hearsay. State v. DiMaggio, 49 Wis. 2d 565, 182 N.W.2d 466 (1971). An officer need not be in possession of a warrant to make a valid arrest. Schill v. State, 50 Wis. 2d 473, 184 N.W.2d 858 (1971). An arrest was valid when a defendant, approached by an officer, voluntarily stated that he assumed they would be looking for him because he had been the last person to see the victim alive. Schenk v. State, 51 Wis. 2d 600, 187 N.W.2d 853 (1971). Police have grounds to arrest without a warrant when they have information from a reliable informer that a crime is to be committed, when they check the information, and when the defendants attempt to escape when stopped. Molina v. State, 53 Wis. 2d 662, 193 N.W.2d 874 (1972). A person is not under arrest and the officer is not attempting an arrest, so far as the right to use force is concerned, until the person knows or should know that the person restraining or attempting to restrain him or her is an officer. Celmer v. Quarberg, 56 Wis. 2d 581, 203 N.W.2d 45 (1972). An illegal execution of a valid arrest warrant is not sufficient to result in a loss of personal jurisdiction over the accused. State v. Monsoor, 56 Wis. 2d 689, 203 N.W.2d 20 (1973). The fact that a witness had identified the defendant by photograph was sufficient to support an arrest, even though the witness was not allowed to identify the defendant at the trial. State v. Wallace, 59 Wis. 2d 66, 207 N.W.2d 855 (1973). When an officer, mistakenly believing in good faith that the occupants of a car had committed a crime, stopped a car and arrested the occupants, the arrest was illegal, but a shotgun in plain sight on the back seat could be seized and used in evidence. State v. Taylor, 60 Wis. 2d 506, 210 N.W.2d 873 (1973). Enforcement officers may make constitutionally valid arrests without warrants under sub. (1) (d) if they have reasonable grounds to believe that the person has committed a crime. Rinehart v. State, 63 Wis. 2d 760, 218 N.W.2d 323 (1974). The police force is considered as a unit. If there is a police-channeled communication to the arresting officer who acts in good faith, the arrest is based on probable cause when facts exist within the police department. State v. Shears, 68 Wis. 2d 217, 229 N.W.2d 103 (1975). When bags were heavy and contained brick-like objects obtained in an overnight trip and the defendant's house was under surveillance, there was probable cause for arrest for possession of marijuana. State v. Phelps, 73 Wis. 2d 313, 243 N.W.2d 213 (1976). The test under sub. (1) (d) is whether the arresting officer could have obtained a warrant on the basis of information known prior to the arrest. Police may rely on eyewitness reports of citizen informers. Loveday v. State, 74 Wis. 2d 503, 247 N.W.2d 116 (1976). An officer may make a warrantless arrest for an ordinance violation if a statutory counterpart of the ordinance exists. City of Madison v. Ricky Two Crow, 88 Wis. 2d 156, 276 N.W.2d 359 (Ct. App. 1979). Evidence obtained during a mistaken arrest is admissible as long as the arresting officer acted in good faith and had reasonable, articulable grounds to believe that the suspect was the intended arrestee. State v. Lee, 97 Wis. 2d 679, 294 N.W.2d 547 (Ct. App. 1980). An arrest by an out-of-state police officer was a valid citizen's arrest. State v. Slawek, 114 Wis. 2d 332, 338 N.W.2d 120 (Ct. App. 1983). When a defendant's mother admitted police into her home to talk to her son, the subsequent arrest of her son was valid. State v. Rodgers, 119 Wis. 2d 102, 349 N.W.2d 453 (1984). Municipal police may arrest and detain a person for whom another municipality in another county has issued a civil arrest warrant. 61 Atty. Gen. 275. A city police officer is a law enforcement officer and traffic officer within s. 345.22. 61 Atty. Gen. 419.