[SalesForce] System.JSONException: Malformed JSON: Expected ‘{‘ at the beginning of object

I have getting the below JSON on using JSON.serialize

[ {
  "lname" : "Singh",
  "hcpZipCode" : null,
  "hcpState" : null,
  "hcpEmail" : "test@test.com",
  "hcpCity" : null,
  "hcpAddLine1" : null,
  "fname" : "Abhey",
  "countryCode" : "AUS"
} ]

I don't know why this '[' is coming at the begining.I don't need this '[' at the begining due to which I am getting System.JSONException: Malformed JSON: Expected '{' at the beginning of object

code

   public PageReference step2() {

       string JSONstr='';
       List<HCPRequest> conWrapList = new List<HCPRequest>();
       HCPRequest tempcontactWrapper = new HCPRequest();
       tempcontactWrapper.fname='Abhey';
       tempcontactWrapper.lname='Singh';
       tempcontactWrapper.countryCode='AUS';
       tempcontactWrapper.hcpEmail=contact.Email;
        conWrapList.add(tempcontactWrapper);

        JSONstr = JSON.serializePretty(conWrapList);
        System.debug('\n******'+JSONstr +'\n******');

        String clientId = 'xy';
        String clientSecret = 'x';

        //We can also store our username password in custom setting.
        String username='x';//salesforce username 
        String password='x';//password+securitytoken
        // Generating the Access Token
        HttpRequest req = new HttpRequest();
        req.setMethod('POST');
        req.setEndpoint('https://test.salesforce.com/services/oauth2/token');// this is the OAuth endpoint where this request will be hit
        req.setBody('grant_type=password&client_id='+clientId+'&client_secret='+clientSecret+'&username='+username+'&password='+password);

        Http http = new Http();
        HTTPResponse res = http.send(req);
        String str = res.getBody();
        wrapObj = (Wrapper)Json.deserialize(str,Wrapper.class);
        accessToken = wrapObj.access_token;
        instanceUrl = wrapObj.instance_url;

        HttpRequest req1 = new HttpRequest();
        string response='';
        req1.setMethod('POST');
        //req.setEndpoint(wrapObj.instance_url+'/services/apexrest/Account/getAccountById?name=champaKAli');
        string EndPt = 'y';
        string email='test@test.com';
        req1.setEndpoint(EndPt);
        req1.setHeader('Authorization', 'OAuth '+wrapObj.access_token);
         req1.setHeader('Content-Type', 'application/json');
         //req1.setBody('{"request":{"lname" : "Singh","hcpZipCode" : null,"hcpState" : null,"hcpEmail" : "test@test.com","hcpCity" : null,"hcpAddLine1" : null,"fname" : "Abhey","countryCode" : "AUS"}}');
         req1.setBody('{"request":'+JSON.Serialize(conWrapList)+'}');
         //req.setBody('{"request": {"countryCode": "AUS","hcpEmail" : ""+email}}');

        //req.setTimeout(60000);



         //req.setHeader('Content-Length', '0');
        Http http1 = new Http();
        HTTPResponse res1 = http1.send(req1);

        System.debug('***Response***** ' + res1.getBody());
        if(res1.getBody()!=null)
        {
            response=res1.getBody();
            HCPResponse saj=(HCPResponse)JSON.deserialize(response,HCPResponse.class);
          System.debug('***Response came full***** ' + saj);
           System.debug('***Response came***** ' + saj.accList);

           for(HCPResponseDetail s :saj.accList)
           {
           System.debug('***Response email***** ' + s.hcpEmail);
           System.debug('***Response add2***** ' + s.hcpAddrLine2);
           contact.Address1_Line2__c=s.hcpAddrLine2;
           }


        //return response;
        //string methodcall=methodGet(JSONstr);


            return Page.opptyStep2CustomReg;
        }