OPINION OF THE COURT
Hawkins, J.The defendant appeals from a judgment of the County Court, Nassau County, rendered April 19, 1976, convicting him of grand larceny in the third degree, upon a jury verdict, and imposing sentence. The appeal also brings up for review the denial, after a hearing, of the defendant’s motion to suppress certain evidence.
The judgment should be reversed, on the law, the motion to suppress granted and a new trial ordered.
On August 28, 1975, at approximately 2:00 p.m., two police officers who were on patrol at a shopping center located in Valley Stream, New York, entered Gimbels Department Store. They had been informed by one of the store’s security personnel that the appellant, who was then in the men’s clothing department, was being watched. After observing appellant for some 5 to 10 minutes, during which time nothing transpired, they left the store.
Thereafter, a security officer of the store saw the appellant take wire clippers and cut the chains running through the sleeves of some six leather coats. Appellant then placed the coats in a large plastic bag and proceeded to leave the store with the bag. The police officers, who had resumed patrol, were stopped by a security guard from Gimbels and informed that their assistance was needed because other security personnel were about to stop the subject, who was leaving Gimbels.
The officers entered the shopping mall, where they saw two security personnel from Gimbels and the appellant, who had been stopped and positioned against a wall. In front of the appellant was a plastic bag containing clothing. As they approached, Officer Kuhlkin spoke to the appellant, identifying himself as a police officer and displaying his shield. Kuhlkin placed his hand on the appellant’s shoulder while the latter was being handcuffed by the store’s security guards.
The police officers and security personnel walked the appellant into the store’s security office. The officers then left the office and waited in the lobby immediately adjacent to that office for some 15 to 20 minutes, re-entered the office and then *267transported the appellant to Nassau County’s Fifth Police Precinct station house. Police Officer Conroy, the other officer involved, testified that as far as he was concerned, the appellant was not free to leave the store during the time he and Kuhlkin were outside the security office. Neither officer told the appellant that he was under arrest. The officers did not question the appellant in the security office; nor were they present when the security personnel questioned him. During that period appellant signed a statement which amounted to a full confession to the theft of the coats. He also signed photographs taken of the coats and other items. At no time was he advised of his Miranda rights.
After a pretrial hearing, the court denied the appellant’s motion to suppress the statement and photos he had signed. The court ruled that the statement was voluntary and "that Miranda was inapplicable * * * [because] the function of the police * * * was not as police officers in their own right but rather [they] were assisting the store personnel.” The appellant’s statement was introduced at the trial and he was convicted.
Two questions are presented on this appeal: (1) was it proper not to have suppressed the statement and photos; and (2) if not proper, was their admission into evidence harmless error? We answer both these questions in the negative.
It is axiomatic that if a confession is obtained without the knowledge or participation of the police, it is fully admissible at a trial (People v Horman, 22 NY2d 378, cert den 393 US 1057). Even where there is police participation—if it is sufficiently limited—Fourth Amendment considerations do not come into play (People v Goodman, 51 AD2d 1008).
Here the officers had the appellant under surveillance at the request of the store’s security personnel; their assistance was later requested when the appellant was seen removing the coats. After one of the police officers identified himself, they accompanied the appellant to the security office and waited while he was interrogated. One of the police officers testified that as far as he was concerned the appellant was not free to leave during this time. The participation of the police was of sufficient level to require that Miranda warnings be given. Thus, it was error not to have granted the appellant’s motion to suppress.
We must now determine whether this error, which is constitutional in nature, is, nevertheless, harmless under the *268standards enunciated in People v Almestica (42 NY2d 222). There the court held (pp 224-226) that "[e]ven constitutional error may be harmless when * * * it is clear, beyond a reasonable doubt, that * * * [it] did not contribute to * * * [the defendant’s] conviction * * * So long as there is no reasonable possibility that admission of the evidence contributed to the conviction * * * the error * * * [is] harmless and the conviction should not be nullified as a matter of law.”
The People argue that in the light of the eyewitness testimony, the conviction can be sustained even if the confession is deemed illegal. One of the store’s security personnel testified that he saw the entire incident since he had had the appellant under observation. Another testified that he saw the appellant remove the coats from the rack and later saw him carrying a plastic bag from the store. The People contend that the appellant’s confession merely corroborated that and other evidence. The essential question still remains: Is there a reasonable possibility that the admission of the appellant’s statement into evidence contributed to his conviction? With the possible exception of a confession from the stand, nothing could have damned the appellant more than his written admission of guilt. Indeed, it could be said that the other trial evidence corroborated this statement and not the converse, as the People urge.
Under the circumstances present, we cannot say beyond a reasonable doubt that the error in admitting the appellant’s statement did not contribute to his conviction.