Officer Gallo of the Marblehead police department was on routine patrol when, shortly after midnight on February 27, 2007, he saw the juvenile walking up the driveway of Marblehead High School. It was a school night, but long after school was closed. The officer approached and asked for the juvenile’s name, age, and destination. In response, the juvenile *371gave his name and said that he was fifteen years old, that he was a student at the high school, and that he was walking home. Officer Gallo knew that the high school had a policy prohibiting people on its property after 10:00 p.m. unless there was a school function. The purpose of the policy was to avoid vandalism. The officer also knew that students, such as the juvenile, were required to sign a sheet containing the school’s rules. He told the juvenile that the school prohibited him from being on school grounds and said that he would drive him home. The juvenile agreed. Officer Gallo would not have allowed the juvenile to leave once he told him that he was going to drive him home.
Although the officer believed that he had probable cause to arrest the juvenile for trespassing, he had no intention of doing so. Instead, Officer Gallo simply intended to drive the juvenile home to his parents, as he did with any teenager1 he came across who was out after midnight. Because Officer Gallo intended to put the juvenile in the back seat of his police cruiser without handcuffs, he told the juvenile that he would pat frisk him for weapons before the juvenile sat behind him in the cmiser. This too was one of the officer’s standard procedures, designed to ensure his safety.
In the small of the juvenile’s back and under his baggy sweatshirt, Officer Gallo felt a hard object of five inches by four inches that had a ninety degree angle. When Officer Gallo touched his back, the juvenile “freaked out,” striking the officer with his forearm. The juvenile’s reaction, combined with the object’s size and shape, led Officer Gallo to think that what he felt was a weapon. He asked the juvenile to keep his hands out and to calm down. The juvenile did neither, instead flailing his arms, striking the officer, and attempting to keep him away. The two ended up on the ground. By this time, Officer Gallo had called for backup, and Officer Sinclair arrived. Officer Sinclair smelled the odor of burnt marijuana.
The officers removed a cellular telephone and a keychain with three keys from the juvenile’s pockets. Under the juvenile’s sweatshirt was a nylon bag with drawstrings that he was wear*372ing like a backpack.2 While Officer Sinclair stayed with the juvenile, Officer Gallo took the backpack to the front of his car, about twenty feet away, and opened it. Inside was a locked zippered bank bag. It contained the hard object that Officer Gallo had earlier felt, but he could not tell what it was because the bag was locked.
While Officer Gallo was near the front of the car, looking in the backpack, the juvenile and Officer Sinclair began to wrestle after the juvenile (who was not handcuffed) reached his cellular telephone and made a call.3,4 Officer Gallo returned to the back of the car, and the juvenile was handcuffed and told that he was under arrest for trespassing and resisting arrest.
The juvenile was taken to the station, where he was asked to give permission to open the locked bank bag. He did not respond. Officer Gallo tried unsuccessfully to open the bag with the three keys that had been removed from the juvenile’s pockets. Officer Gallo and the lieutenant on duty asked the juvenile’s mother and her boyfriend (who had come to the station with her) for permission to open the bag. The boyfriend consented, but the mother said nothing. Officer Gallo then used a pocket knife to cut the stitching of the bag and opened it. Inside were (1) a digital scale, (2) a plastic bag containing twelve smaller plastic baggies, each containing marijuana, (3) a plastic bag containing two buds of marijuana, (4) some empty plastic baggies, and (5) ninety-one dollars in cash.
The juvenile was charged in delinquency complaints with trespassing (G. L. c. 266, § 120), resisting arrest (G. L. c. 268, § 32B), distribution of a class D substance (marijuana) (G. L. c. 94C, § 32C), and a drug violation in a school zone (G. L. c. 94C, § 32J). After a bench trial, he was adjudicated delinquent of all charges except trespassing.
*3731. Motion to suppress. The juvenile appeals from the denial of his motion to suppress the contents of the locked bank bag, which he contends were seized in violation of the Fourth Amendment to the United States Constitution and art. 14 of the Massachusetts Declaration of Rights.5 He focuses on three events, all of which he contends were unconstitutional: the initial patfrisk, the search of the backpack at the scene, and the opening of the bank bag at the station. Although the juvenile contends that all three are unconstitutional, we need not consider the first two because neither yielded anything that the juvenile sought to suppress or that, as a practical matter, supports the drug charges against him.6 It was not until the officers reached the station that the drugs and drug paraphernalia were found. We, therefore, begin with the station house search, which the Commonwealth defends as a valid inventory search.
The Marblehead police department’s inventory policy provides, “Any container or article found on the arrestee’s person or carried by him shall be opened and its contents inventoried.” The juvenile argues that the policy is impermissibly vague because it “is silent with respect to locked containers versus closed containers.”
An inventory search must be reasonable, South Dakota v. Opperman, 428 U.S. 364, 372-373 (1976), and to determine whether it is, “we must ‘balanc[e] its intrusion on the individual’s Fourth Amendment interests against its promotion of legitimate *374governmental interests.’ ” Illinois v. Lafayette, 462 U.S. 640, 644 (1983), quoting from Delaware v. Prouse, 440 U.S. 648, 654 (1979). “A range of governmental interests supports an inventory process.” Illinois v. Lafayette, 462 U.S. at 646. These interests include protecting the arrestee’s property, protecting the police from false claims of theft, and public safety. See ibid. An inventory search of “every item carried on or by a person who has lawfully been taken into custody by the police will amply serve the important and legitimate governmental interests involved.” Id. at 648.
Although it is not unreasonable for police officers to conduct an inventory of “any container or article” — including closed containers — in a person’s possession, the search must follow “established inventory procedures.” Ibid. See Colorado v. Ber-tine, 479 U.S. 367, 376-377 (1987) (Blackmun, J., concurring) (“Thus, it is permissible for police officers to open closed containers in an inventory search only if they are following standard police procedures that mandate the opening of such containers in every [case]”); Commonwealth v. Caceres, 413 Mass. 749, 755 (1992) (“an unlocked closed container may be searched pursuant to specific written police inventory procedures without violating art. 14”). “Police procedures can be considered ‘standard’ only if they are set forth in writing.” Commonwealth v. Garcia, 409 Mass. 675, 681 (1991), quoting from Commonwealth v. Bishop, 402 Mass. 449, 451 (1988).
The underlying rationale for the inventory exception to the Fourth Amendment and art. 14 is the same: police “are not vested with discretion to determine the scope of the inventory search.” Colorado v. Bertine, 479 U.S. at 376. See Commonwealth v. Ros-tad, 410 Mass. 618, 622 (1991). The written policy must be “explicit enough to guard against the possibility that police officers would exercise discretion with respect to whether to open closed [containers] as part of their inventory search.” Ibid. It is “unreasonable to expect police officers in the everyday course of business to make fine and subtle distinctions in deciding which containers or items may be searched and which must be sealed as a unit.” Illinois v. Lafayette, 462 U.S. at 648.
Here, the policy was insufficiently precise in two respects. First, it did not spell out what to do with locked containers as *375opposed to those that are simply closed. As a subset of this, the policy also did not spell out what should be done with a locked container for which the officers have the key and a locked container for which they do not.7 Second, accepting the Commonwealth’s position that the bank bag was “opened” pursuant to the policy requires stretching the meaning of “open” to a degree that would allow officers to choose among a limitless range of options, including (as here) destruction.
We have found no case that would permit an officer to break into or damage a locked container in order to conduct an inventory search. The purpose of an inventory is to protect the property of the owner and to protect officers from claims by the owner that the property was damaged. Permitting an officer to destroy or break into a locked container runs counter to the very purpose of the inventory exception. See Tennessee v. Cabage, 649 S.W.2d 589, 592 (Tenn. 1983). Moreover, breaking into the locked bank bag served no noninvestigatory purpose. There is no suggestion that the bag presented an immediate danger that required that it be opened immediately to protect public safety.
We conclude that the contents of the locked bank bag were not obtained as a result of a legitimate inventory search and, therefore, should have been suppressed. Suppression of the contents of the locked bank bag in turn requires that the adjudications based on the drug charges be reversed, there being no other evidence to support those charges. That being the case, whether the patfrisk or the search incident to arrest were valid are questions we need not, and do not, reach. Neither resulted in the discovery of evidence to support any of the adjudications.
2. Sufficiency of the evidence. Viewed most favorably to the Commonwealth, the evidence was more than sufficient to support the charges of resisting arrest.8 Officer Gallo told the juvenile that he was under arrest as soon as he and the juvenile “fell down the first time” at “[t]he very beginning of the struggle.” *376Thereafter, the juvenile kept struggling with Officer Gallo. He also physically struggled with Officer Sinclair. See Commonwealth v. Grant, 71 Mass. App. Ct. 205, 208 (2008) (resisting arrest charge appropriate where the person has been seized or detained for the purpose of effectuating an arrest, and the person understands that); G. L. c. 268, § 32B. The juvenile’s mother testified that she heard a scuffle involving the juvenile when he called her on his cellular telephone after his arrest. These circumstances are far different from those in Commonwealth v. Smith, 55 Mass. App. Ct. 569, 574-576 (2002), upon which the juvenile relies, where the physical confrontation occurred during an investigatory stop, not in connection with an arrest.
For the reasons set forth above, the adjudication of delinquency for resisting arrest (G. L. c. 268, § 32B) is affirmed and the adjudications of delinquency for distribution of a class D substance (marijuana) (G. L. c. 94C, § 32C), and a drug violation in a school zone (G. L. c. 94C, § 32J) are reversed.
So ordered.
Officer Gallo’s practice was to drive home anybody under the age of sixteen who was out after midnight, unless he had spoken to their parents beforehand.
In order to remove the backpack, the officers first had to remove the juvenile’s sweatshirt.
Officer Sinclair, having been trained that cellular telephones could be used as weapons, took it away.
The juvenile called his mother. When she answered the telephone, she heard the juvenile on the other end seemingly engaged in a struggle. The telephone then went dead. Understandably alarmed, she called the police department and was told that the juvenile was under arrest and being brought into the station. She then went to the station with her boyfriend.
The juvenile’s motion sought to suppress “marijuana, two medium sized buds, in clear ziploc bags, marijuana in twelve small bags within one ziploc bag, and one dodo digital scale.” It also presumably sought to suppress the bank bag, although it did not specifically state so.
Even assuming, as the Commonwealth contends, that the backpack was opened incident to arrest, the items were not obtained as a result of that search. The scope of a search incident to arrest has spatial and physical limitations, which preclude considering the search at the station to be incident to arrest. See, e.g., Arizona v. Gant, 129 S. Ct. 1710, 1723 (2009) (police are authorized to search a vehicle incident to a recent occupant’s arrest only when the arrestee is unsecured and “within reaching distance of the passenger compartment at the time of the search”); Commonwealth v. Alvarado, 420 Mass. 542, 554 (1995) (search must be contemporaneous with the arrest); Commonwealth v. Elizondo, 428 Mass. 322, 323 (1998) (search must be within the area of the defendant’s immediate control); Commonwealth v. Pierre, 72 Mass. App. Ct. 580, 585-587 (2008), S.C., 453 Mass. 1010 (2009) (discovery of contraband during an inventory search at a police station one to one and one-half hours after an arrest was not “incident” to that arrest).
We note by way of contrast that the State police department’s policy distinguishes between locked containers for which a key is available, and locked containers for which no key is available. See Commonwealth v. Difalco, 73 Mass. App. Ct. 401, 403 (2008)
Because of our decision regarding the motion to suppress, we need not address the juvenile’s argument regarding the sufficiency of the evidence on the drug charges. Were we to have reached the question, however, we would have found that the evidence was sufficient to support the adjudications.