Random EXC_BAD_ACCESS in SQLite operations

Question

We are using SQLite database in our app. We are having plenty of select, update and insert SQLite operations. Our app is crashing randomly with below stack trace in CrashAnalytics.

Crashed: com.apple.main-thread
EXC_BAD_ACCESS KERN_INVALID_ADDRESS 0x736e617274206f72
0  libsqlite3.dylib               0x18de5143c sqlite3_rekey + 112316
1  libsqlite3.dylib               0x18de51438 sqlite3_rekey + 112312
2  libsqlite3.dylib               0x18de51474 sqlite3_rekey + 112372
3  libsqlite3.dylib               0x18de51474 sqlite3_rekey + 112372
4  libsqlite3.dylib               0x18ddd1b2c sqlite3_log + 36424
5  libsqlite3.dylib               0x18de52688 sqlite3_rekey + 117000
6  libsqlite3.dylib               0x18ddcab20 sqlite3_log + 7740
7  libsqlite3.dylib               0x18ddb067c sqlite3_exec + 20292
8  libsqlite3.dylib               0x18ddac9a4 sqlite3_exec + 4716
9  libsqlite3.dylib               0x18ddac1d0 sqlite3_exec + 2712
10 libsqlite3.dylib               0x18ddabf24 sqlite3_exec + 2028
11 My App                    0x10010abb8 -[DataHelper getAccountType:] (DataHelper.m:6677)
12 My App                    0x1001a69e4 -[InvoicePurchase postInvoiceAlert:] (InvoicePurchase.m:3203)
13 libdispatch.dylib              0x18c7629e0 <redacted> + 24
14 libdispatch.dylib              0x18c7629a0 <redacted> + 16
15 libdispatch.dylib              0x18c7675e8 _dispatch_main_queue_callback_4CF + 996
16 CoreFoundation                 0x18d8590c8 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
17 CoreFoundation                 0x18d856ce4 __CFRunLoopRun + 1572
18 CoreFoundation                 0x18d786da4 CFRunLoopRunSpecific + 424
19 GraphicsServices               0x18f1f1074 GSEventRunModal + 100
20 UIKit                          0x193a42470 UIApplicationMain + 208
21 My App                    0x1001b719c main (main.m:18)
22 libdyld.dylib                  0x18c79559c <redacted> + 4

Below is the SQLite code:

sqlite3_stmt *statement=NULL;
NSString* accountType = NULL;
NSString *querySQL = [NSString stringWithFormat: @"SELECT a_type FROM account_detail WHERE aname=\"%@\"", accountName];
const char *query_stmt = [querySQL UTF8String];
if (sqlite3_prepare_v2(dbNameCompany, query_stmt, -1, &statement, NULL) == SQLITE_OK) //Line 6677 of DataHelper.m
{
    if (sqlite3_step(statement) == SQLITE_ROW)
    {
        accountType = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
    } 
    else 
    {
    }
}
sqlite3_finalize(statement);
return accountType;

Any help?